The Mosquitoes of Illinois ( Diptera, Culicidae)

Home , America (shipwreck), Home (schooner), Orthopodomyia, Orthopodomyia signifera, Psorophora cyanescens, Success (shipwreck)

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Urbana, Illinois Imam= B

( OF ILLINOIS HERBERT THE MOSQUITOES DIPTERA, CULICIDAE) ULLETIN OF THE ILLINOIS NATURALHISTORYSURVEY DEPARTMENT OF H.

STATE [ITOSS FRANK

DWIGHT H.GREEN, Printed HARLOW B. REGLSTRA.T1ON l a

TWIN! by OF Authorityof ILLINOIS PSON, Gal MILLS,

Director vermor ch. AND EDUCATION

CHIEF STATE OF ILLINOIS DWIGHT H. GREEN, Governor DEPARTMENT OF REGISTRATION AND EDUCATION FRANK G. THOMPSON, Director

NATURAL HISTORY SURVEY DIVISION HARLOW B. MILLS, Chief

Volume 24 BULLETIN Article I

The Mosquitoes of Illinois ( Diptera, Culicidae)

HERBERT H. ROSS

Printed by Authority of the State of Illinois

URBANA, ILLINOIS

flugust 1947 STATE OF ILLINOIS DWIGHT H. GREEN, Governor DEPARTMENT OF REGISTRATION AND EDUCATION FRANK G. THOMPSON, Director

BOARD OF NATURAL RESOURCES AND CONSERVATION FRANK G. THOMPSON, Chairman CARL G. HARTMAN, Ph.D., Biology GEORGE D. STODDARD, Ph.D., President L. H. TIFFANY, Ph.D., Forestry of the University of Illinois L. R. HowsosT, B.S.C.E., C.E., Engineering WALTER II. NEWHOUSE, Ph.D., Geology ROGER ADAMS, Ph.D., D.Sc., Chemistry

NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF HARLOW B. MILLS, Chief BESSIE B. HENDERSON, M.S., .43.fiStant to the Chief

Section of Economic Entomology Section of Aquatic Biology Entomologist G. C. DECKER, Ph.D., GEORGE W. BENNETT, Ph.D., Litt/110/0.92St J. H. BIGGER, M.S., Associate Entomologist D. F. HANssN, Ph.D., Assistant Zoologist L. I,. ENGLISH, Ph.D., Research Entomologist PAUL G. BARNICKOL, M.A., Ichthyologist S. C. CHANDLER, B.S., Southern Field Ento- ELIZABETH B. CHASE, Ph.D., Research mologist Assistant JAMES W. APPLE, M.S., Northern Field Ento- mologist Section of Game Research and Management C. J. WniNmAN, Ph.D., Associate Entomolo- gist R. E. YEATTER, Ph.D., Game Specialist JOHN M. WRIGHT, B.A., Assistant Entomol- DEAN H. ECKE, Assistant in Game Research ogist WILLIS N. BRUCE, B.S., Assisitant Entomolo- Section of Migratory Waterfowl gist II. B. PETTY, JR., M.A., Associate in Ento- F. C. BELLROSE, JR., B.S., Associate Game mology Extension Technician GEORGE F. LUDVIK, M.A., Special Research HAROLD C. IIANSON, M.S., Assistant Game Assistant Technician JOHN E. PGRTER, M.S., Laboratory Assistant CLARA Z. EISENBERG, B.S., Laboratory Assist- Cooperative Wildlife Research (With State ant Department of Conservation and U. S. Fish and Wildlife Service) Section of Eaunistic Surveys and Insect Identi- fication C. C. SWEARS, M.F., Project Leader H. H. Ross, Ph.D., Systematic Entomologist GEORGE C. ARTHUR, B.S., Project Leader CA ,L 0. MOHR, Ph.D., Associate Entomolo- PAUL J. NlooRE, B.S., Project Leader gist, Artist (on leave) A. B. COWAN, B.S.F., Assistant Project Leader B. D. BURRS, Ph.D., Assistant Entomologist MILTON W. SANDERSON, Ph.D., Assistant Section of Applied Botany and Plant Pathology Entomologist LEO R. TEHON, Ph.D., Botanist LEWIS J. STANNALD, JR., B.S., Assistant Ento- J. C. CARTER, Ph.D., Associate Botanist mologist G. H. BOEWE, M.S., Field Botanist ELIZABETH N. MAXWELL, B.A., Artist, Ento- mological Assistant J. L. FORSBERG, M.S., Research Pathologist PHYLLIS A. BEAVER, Laboratory Assistant ROBERT A. EVERS, M.S., Assistant Botanist

Section of Forestry Section of Publications WILLET N. WANDELL, M.F., Forester JAMES S. AYARS, B.S., Technical Editor LAWSON B. CULVER, B.S., Extension Forester FRANCES B. KIMBROUGH, B.S., Assistant Tech- Technical Library nical Editor MARGUERITE SIMMONS, M.A., M.S., Techni- ROBERT E. HESSELSCHWERDT, B.A., Assistant cal Librarian Technical Photographer CONSULTANTS IN HERPETOLOGY: HOWARD K. GLOYD, Ph.D., Director of the Museum, Chicago Academy of Sciences; CLIFFORD H. POPE, B.S., Curator of Amphibians and Reptiles, Chicago Natural History Museum. This paper is a contribution from the Section of Insect Survey. (17533-1800-5-46) CONTENTS

BIOLOGY ...... 1 Eggs.—Larvae.--Pupae.--Adults.-----Hibernation.—Habitat Preferences. SEASONAL DISTRIBUTION ...... 8 DISTRIBUTION PATTERN ...... 8 ECONOMIC IMPORTANCE ...... 9 CONTROL CONSIDERATIONS ...... 9 COLLECTING AND PRESERVING ...... 10 Larvae.—Adults.—Labeling. STUDY TECHNIQUES ...... 12 Larvae.—Adults. REARING ...... 13 Individual Rearings.—Group Rearings.—Larval Food.—Temperature, Aeration, and Sunlight. CLASSIFICATION ...... 14 Terminology.—Literature.—Material Studied.--Acknowledgments. KEY TO SUBFAMILIES ...... 16 CIIAOBORINAE ...... 17 CULICE■TAE ...... 17 Mosquitoes of Illinois ...... 17 Key to Genera ...... 17 Anopheles ...... 24 Me garhinus 32 LI ranotaenia ...... 33 Wye° nzyia ...... 34 Mansonia ...... 35 Ort/zopodomyia ...... 36 Culiseta ...... 37 Cu/ex ...... 40 A edes...... 52 P sorophora ...... 82 LITERATURE CITED ...... 93 INDEX ...... 95 One of the largest Illinois mosquitoes is the "gallinipper," Psorophora ciliata, which may attain a wingspread of 15 mm. (over half an inch). It is a vicious biter and is generally distributed over Illinois. The larvae or wigglers of this species breed in rain pools and have the habit of feeding on larvae of other mosquito species. The Mosquitoes of Illinois ( Diptera, Culicidae)

HERBERT H. ROSS

OSQUITOES are midgelike insects second by summarizing information regard- of various sizes, some of them ing the distribution, biology, and habitat Mminute, some of them nearly a half preferences of the species. inch long. They belong to the family Culici- dae, which belongs to the order Diptera, BIOLOGY embracing the common housefly and other two-winged flies. Mosquitoes have aquatic Mosquitoes, in common with other groups larvae called wiggle-tails, wigglers, or wrig- of flies, have four distinct stages in their life glers, which transform to aquatic pupae history: (1) the egg, laid by the female; called tumblers. The adults, which emerge (2) the larva, wiggle-tail, wiggler, or wrig- from the pupae, are aerial. gler; (3) the pupa, or tumbler; and (4) About 150 species of mosquitoes are the adult fly. known to occur in the United States and Canada, and 52 of these have been taken in Eggs Illinois. The Illinois mosquito fauna represents a combination of the northern and the Eggs deposited by Illinois species of mos- southern mosquito faunas, a combination quitoes fall into three fairly distinct cate- not yet treated in the various reports giving gories: (1) those laid singly on water; (2) keys to the faunas of limited regions. those glued together in rafts that float on Mosquitoes are a real nuisance in many water; and (3) those laid singly in damp parts of Illinois. Although some of the humus or other semidry material. more intensively farmed areas are compara- Eggs Laid Singly on Water.—In this tively free from all but local incursions of category belong the eggs of Anopheles, fig. mosquito broods brought on by unusual 1 C. They are elongate oval, usually pointed weather conditions, in all other parts of the at one end, and have a pair of lateral floats. state mosquitoes are a perennial problem. From 100 to 300 eggs may be laid by an An extremely vicious biter, the salt marsh adult female after taking a blood meal; mosquito, Aedes sollicitans, has invaded a usually the eggs hatch in a few days. Little few Illinois cities. The malaria mosquito, is known about the eggs of the tree hole Anopheles quadrimaculatus, is a menace to genus Megarhinus except that they are laid human health in some areas. To be eco- singly on the surface of water. Anopheles nomical as well as effective and thorough, a and Meyarhinus are the only genera in this control program for these and other mos- class known to occur in Illinois. quitoes must be based on accurate identifica- Eggs Laid in Rafts on Water.—The eggs tions of the species involved and a knowl- of many mosquito genera are deposited side edge of their peculiarities of life history and by side in such a manner as to form a raft, habits. fig. 1,/. This raft floats on the surface of The nation's annual "mosquito bill" is water, and the eggs hatch in a few days, high—probably $100,000,000 due to mos- each larva escaping from its egg at the end quito-borne diseases, and close to $50,000,- that touches the water. The raft may con- 000 for screening, pest control programs, tain a hundred eggs or more. In the genera and depressed real estate values. Culex, Culiseta, Mansonia, and Uranotae- The object of this paper is to provide nia, eggs are deposited in rafts. The larvae means for making mosquito control pro- of all these groups breed in permanent bod- grams more effective, first by furnishing ies of water. illustrated keys and descriptions for the Eggs Laid Singly in Semidry Places.— identification of mosquito species that occur In many genera of mosquitoes, including in Illinois and states similar in climate, and rledes, Psorophora, Orthopodomyia, and [ 1 ] 2 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

Wyeomyia, the eggs are laid out of water, known as intermittent breeders. They in- but they do not hatch until water has risen clude all species of Psorophora and certain and inundated them. The eggs may be laid species of Aedes: vexans, sollicitans, trivit- either just above the water line in such sit- tatus, and Many southern species. In the uations as tree holes, various water contain- other class, called annual breeders, because ers, and marsh edges, or in damp humus in only one generation is developed each year, the bottoms of recently dried-up pools that the eggs must be subjected to winter freez- are subject to periodic flooding. The eggs ing before they develop. Eggs laid by tile of Aeries, fig. 1 B, and Psorophora, normally adults of one generation do not hatch with

4 , GIIRAL ZIFftv .14*PERSIv SLABIAT> YISE..zGOTTOIRAR wtovt mitgartattgee,:zu.rtz

Fig. 1.—Eggs of mosquitoes: 4, Culex restuans; B, riedes taeniorhynchus; C, Anopheles guadrimaculatus. ( After Howard, Dyar, & Knah.)

laid in damp humus, are adapted to with- summer flooding but lie dormant through stand desiccation and may lie dormant 1 or the winter and hatch the next spring. To 2 years without losing their viability. W.Ve- this class belong many species of rledes, omyia lays its eggs above the water line in the such as grossbecki, stimulans, and implaca- pitcher plant, and these eggs do not hatch bills. until the water within the pitcher rises. The same habit is a characteristic of the Larvae tree-hole mosquitoes, Orthopodomyia and Aeries triseriatus and aegypti, which lay eggs The mosquito larva or wriggler, fig. 2, on the sides of tree holes or water contain- has a distinct head, broad thorax, and tubu- ers just above the edge of the water so that lar abdomen. It lives only in water. The with a rise in the water level the eggs hatch. larval period is one of feeding, during which The species of Psorophora and riedes„ the small larva hatching from the egg grows which lay their eggs out of the water, may to a size large enough to produce the adult be divided into classes with respect to sig- fly. Unlike the adult, this larva has no nificant differences in egg hatching. In one beak and does not suck food; instead it has class the eggs hatch as soon as they are a series of brushlike rakes in addition to the flooded; since in this species the life history grinding and grasping mouthparts, a combi- is completed rapidly, several generations nation enabling it to strain, scoop, and ingest usually are produced in a summer as pools small aquatic organisms and particles of dry and flood with alternate dry and rainy plant or animal matter floating in or upon periods. Species belonging to this class are the water or resting on the bottom. In the ugust, 1947 ROSS: MOSQUITOES OF ILLINOIS 3

few genera in which the larvae are preda- The larvae of Illinois mosquitoes may be ceous on other mosquito larvae, the mouth- divided into two distinct types on the basis parts are sharp-toothed for grasping and of breathing structures and feeding habits, swallowing the prey. the anopheline type and the culicine type. In Unlike fish, the wriggler does not obtain the anopheline type (including only the genus oxygen from the water by means of gills. Anopheles), the larvae normally rest paral- When in need of air, the larva in most spe- lel to the surface, touching the surface ten- cies swims upward until it is just below the sion membrane, fig. 11. They have no air surface of the water, if it is not already tubes; the spiracles form a fiat structure on there, and sticks the breathing apparatus (in the back of segment 8. The larvae normally some species a tube and in others a plate), twist their heads through a 180-degree angle which is near the end of the abdomen, and feed on microorganisms or other parti- through the surface tension membrane into cles at or on the surface, but occasionally actual contact with the air, fig. 2. With the feed below the surface much as do culicine larva in this position, the air inside the body larvae. When disturbed they swim to the is exchanged for, fresh air above the water. bottom and hide. In the culicine type, the Among Illinois mosquitoes, only the larva larvae normally feed on or near the bottom of Mansonia does not come to the surface and come to the surface only periodically for for air. In this species, fig. 18, the air tube air. This group includes all of the Illinois forms a sharp, piercing organ, which is mosquitoes except Anopheles, and all of them thrust into the air chambers in the under- have distinct air tubes. The predaceous water portions of marsh plants such as the species, such as Psorophora riliata, do not cattail. The larva of Mansonia obtains its feed on bottom microorganisms but usually oxygen entirely from this source. cruise near the bottom and grasp their prey

Fig. 2.—Larvae of mosquitoes: A, Anopheles; B, Culex. ( After King, Bradley, & McNeel.)

4 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. .1

are broken down and reorganized into the structures of the adult, generally lasts only a few days. At the end of that time the mature pupa comes to the surface of the water, and the adult within it breaks the pupal skin, crawls out onto the surface of the water, and flies away.

Adults

Mosquito adults, fig. 4, are fairly small, delicate, winged flies, quite slender, and always with long, spindly legs. All the adults of the true mosquitoes have beaks. The visible part of the beak is a scabbard Fig. 3.—Pupa of mosquito. (After King, or sheath in which a group of extremely Bradley, & McNeel.) fine stylets makes up a needle-like piercing and sucking organ; it is the function of the there. The curious genus Mansonia is also sheath to keep this slender needle straight included in this group although, as mentioned when it is thrust through the skin of the above, it does not come to the surface for animal upon which the female mosquito air. It is a true bottom feeder. feeds. Both males and females fly with a distinct humming or buzzing sound. Pupae Only the female mosquito "bites," or feeds upon animals; the male feeds on nec- The pupae do not feed but they breathe tar and water. Whereas the female seeks in the same manner as the larvae; the air out her prey and may travel long distances tube is situated on the thorax, fig. 3, instead to it, the male is relatively inactive, gener- of near the end of the abdomen as in the ally hiding in grass or shrubbery except dur- larvae. The pupal stage, in which the mus- ing the mating flights. There is evidence cular and other body structures of the larva that the female does not bite for several

441 -ftmas, 011 1.1.MMENIMIMIEMINIMMP

Fig. 4.—Adult of Aedes aegypti. (From photograph, loaned by the U. S. Public Health Service, of model in the American Museum of Natural History.) August, 1947 Ross: MOSQUITOES OFILLINOIS 5

days after she becomes an adult. Not all The males die with the advent of cold species bite humans. Some feed on nectar, weather. The females hide in hollow trees, and it is thought that a few others feed cellars, manholes, and other sheltered places, chiefly either on plant juices or the blood of from which they emerge in spring and lay birds and small mammals. eggs. Females of most species seek their blood meal during the dusk and night periods. Habitat Preferences Many of these same mosquitoes attack readily in the late afternoon or on cloudy The various species of mosquitoes differ days and during the dawn period. The greatly in the type of habitat frequented woodland species almost invariably bite by the larvae. Some species breed in a great throughout the day, although their attacks variety of situations, whereas others are are usually most vicious during the crepus- extremely restricted in their breeding places. cular period. A few species attack readily The following summary outlines in a general in the open during the day time. Probably way the habitats preferred by the Illinois the best known Illinois species having this species. habit is Anopheles walker. Of unusual Running Water.—Anophdes nunctipen- interest is the biting habit of Psorophora nis usually breeds in small streams, fre- cyanescens, which attacks in the open and quenting the edges and shallow areas where during times of bright sunlight. the current is sluggish. This species breeds Flight habits of mosquitoes have been the with equal success in still water. A few subject of considerable study, in which species of Culex sometimes breed in moving marked or colored specimens have been water heavily laden with organic matter released and their recovery in light traps where the current is slow. These same or resting places has been plotted. A spe- species normally breed in still water. cies of mosquito apparently will behave dif- Still Water.—All Illinois species will ferently under different conditions. It is breed in still water, and most of them only usually considered that malaria mosquitoes in still water, chiefly small ponds and pools normally have a flight range of not more of many types, the shallow edges of lakes, than 1 or 2 miles. Probably the longest and the still water in shallow, dense weed flight ranges occur in species of Apt/es. It beds along the edges of streams. Still water is not unusual for summer swarms of iledes habitats are of several types and may be vexans to migrate 2 or 3 miles and possibly classified as permanent, temporary, special- up to 15 miles, and the salt water mosquito, ized, and semidomestic areas. Act/es sollicitans, has been known to migrate PERMANENT AREAS.—All species that lay 40 or 50 miles. Many woodland species eggs on the surface of the water, whether appear to be fairly restricted in their move- singly or in rafts, frequent permanent water ments and seldom leave the piece of woods areas. All prefer areas with shallow water in which they have matured. and little wave action, abundant cover in the The length of life of adult mosquitoes is form of at least moderate aquatic vegeta- not well known. Some of the Anopheles tion, and abundant food in the form of and iledes females undoubtedly live 1 or 2 humus or other organic matter on the bottom months during the summer period. The and floating particles or microorganisms at adults that hibernate have a much longer the surface. Marshes, fig. 5, or shallow life span. ponds with cattails, sedges, and associated aquatic vegetation are ideal for many mos- Hibernation quito species. TEMPORARY AREAS.—In this category are The great majority of Illinois mosquitoes, ponds that fill with water intermittently for including most of the species of ilet/es and variable periods. In all these ponds one of Psorophora, hibernate in the egg stage. A the chief requirements for a good mosquito few species, such as W yeamyia smithii. habitat is that they have ample organic Anopheles barheri, and species of Orthopo- matter (usually in the form of rotting elomyia, hibernate as larvae frozen in pitcher leaves) on the bottom. plants or tree holes in which they breed. In Illinois, temporary ponds are extremely Anopheles, Culex, and at least inornata of varied with respect to how and when they Culiseta overwinter as fertilized females. are filled, where they are situated, and how 6 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 24, Art. 1

Fig. 5.—Marsh near Hinsdale, Illinois. In spring the more abundant mosquitoes at the marsh edge include Culiseta inornata, Aedes fitchii, Aedes vexans, and Culex apicalis. long they last. Most of them fall into one lans, grossbecki, and implacabilis. The same of four classifications: winter seepage ponds, species occur in flooded stump holes, fig. 7. flood plain ponds, summer rain ponds, and Flood plain ponds form with the over- marsh edges. flow and retreat of streams that leave iso- Winter seepage ponds fill up during the lated pools of water scattered throughout winter or early spring with surface or seep- the flood plain. These are favorite places age water from winter precipitation or the for many Aedes, especially the early spring spring thaw. Ponds of this type, fig. 6, may species sticticus, and some Psorophora species. have water in them for several months, but Summer rain ponds form in many depres- during much of this time the weather is too sions during heavy summer rains and remain cold to allow mosquito development. They for periods of a few days or weeks. In support many of our most vicious early these breed Aedes vexans and many species spring Aedes, especially canadensis, stimu- of Psorophora.

Fig. 6.—Woodland pool, Bensenville, Illinois. This spring pool contains an enormous population of Aedes stimulans. It dries up in summer. August, 1947 Ross: MOSQUITOES OF ILLINOIS 7

FIG. 7.—STUMP hole, Bensenville. A favorite habitat of fledes canadensis. Marsh edges that are alternately flooded and cisterns. In Illinois the chief species and exposed by the rise and fall of water found in these situations are Culex restuans, give the same conditions as temporary ponds, pipiens, and quinguefasciatus. In contain- as far as mosquitoes are concerned. These marsh edges or margins, fig. 5, are important mosquito breeding grounds, especially for A edes vexans. SPECIALIZED HABITATS.—TWO situations of unique interest from the standpoint of the mosquito fauna are tree holes and pitcher plants. Each of these may harbor species of mosquitoes found in no other situation. Tree holes, fig. 8, include cavities within standing tree trunks and inside fallen trees ( Jenkins & Carpenter 1946). • - Illinois mosquitoes that are restricted to this habitat include Megarhinus septentrionalis, species of Orthopodomyia, Anoph- eles barberi, and cledes triseriatus. The tree holes fill up either with rain water or with sap that has risen within the wounded 1) tissues. Larvae that live in the tree holes ii; develop much more slowly than is usual for • • 2 NO16-4.." 'V En species living in ponds. Only one Illinois spe- . ; .• 4 .?-1,)!;:: .d • • ,7L. cies of mosquito, Wyeornyia srnithii, breeds . 41), ; • .01 in pitcher plants; it is found in no other R situation. Its larva feeds on decomposing ' . • animal material trapped in the pitcher. SEMIDOMESTIC SITUATIONS.—Several species of mosquitoes breed readily in situations around human habitations. They breed in the water that accumulates in fish ponds, tin FIG. 8.—TREE hole at Starved Rock State cans, or almost any other type of container, Park. This is the habitat for A edes triseria- fig. 9. They may frequent also the accumu- tics, Orthopodomyia species, and Anopheles lation in stopped-up eaves troughs, drains, ba, beri.

8 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art.1

When the spring weather is uniformly cold well into May, and then is followed by a series of warm weeks, early and midsea- son species come out together, and there is little demarcation apparent between seasonal groups.

DISTRIBUTION PATTERN

The mosquito fauna of Illinois resolves itself into three well-marked groups: (1) species of wide distribution, which are generally distributed in Illinois; (2) northern species that have a range widespread to the Fig. 9.—Refuse heap near Wilmette, Illinois. north, and that occur in only the northern Water in the containers is a favorite breeding portion of the state; and (3) southern spe- place for Culex pipiens and restuans. cies that have a range extending only ers that are out of doors and that have in slightly into Illinois and that are only spo- them an abundance of organic material radic north of the southern third of the (neglected fish ponds are the favorites), state. Anopheles punctipennis may breed in enor- The species that are generally distributed mous numbers. if edes aegypti also breeds in include some of our most abundant nui- similar containers, usually those inside build- sance species, such as iledes vexans, trivit- ings. tatus, canadensis, and sticticus, Psorophora ciliata and ferox, Culex pipiens, apicalis, and SEASONAL DISTRIBUTION restuans, and Culiseta inornata. The various mosquito species appear in a Northern species whose range extends fairly definite sequence as the season into northern Illinois include many of the advances. The earliest species are Act/es, annual-breeding large iledes found in the whose larvae develop in the spring pools. glacial bogs and marshes in the extreme In southern Illinois the principal species are northeastern corner of the state. These canadensis, grossbecki, and sticticus, through species are Act/es implacabilis, punctor, the central part of the state canadensis and stimulans, excrucians, fitchii, flavescens, and sticticus, and in the northeastern part stim- cinereus. A few of these, such as flavescens ulans, implacabilis, fitchii, and others. In and punctor, are rarities; excrucians is pres- southern Illinois the first emergence may ent in only moderate numbers; the other occur as early as April 1, in northern Illi- species breed tremendous populations. Other nois by the middle of May, but usually first mosquitoes in this northern group include emergence is about two weeks later than Culiseta morsitans, confined to the tamarack these dates. The early iledes listed above bogs, and Wyeornyia smithii, the pitcher are without exception annual breeders. plant mosquito, which also occurs only in They are followed in rapid succession by tamarack bogs. On the basis of Illinois Culiseta inornata and Culex apicalis. A collecting, Anopheles walker appears to be week or so after these appear, the large in the same group, since in this state it is number of summer species begin to make abundant only in the cattail marshes and their appearance. These include Anopheles, bogs of the northern part; records from several species of Culex, and usually Act/es other states indicate, however, that its range vexans and trivittatus. The summer spe- extends far to the south where marshes are cies continue to breed in suitable locations available. Another northern mosquito taken throughout the summer or intermittently in Illinois is Aedes spencerii, for which our with the summer rains. only record came from the northwestern A third group of species, which includes corner of the state. Culex quinquefasciatus and Uranotaenia Many southern species have been taken sapphirina, may be present early in the sea- in the extreme southern tip of Illinois, most son, but an appreciable population of this of them in the woodland pools of the post group usually does not appear until at least oak flats in the Mississippi River valley. midsummer. The post oak flats list includes iledes f ulvus

ugust, 1947 Ross: MOSQUITOES OF ILLINOIS 9

pollens, dupreei, and grossbecki, Psorophora become so abundant as to interfere with or howardii, and Anopheles crucians. Aeries stop work by man, with a consequent loss thibaulti has been taken near Carbondale, of labor and accomplishment. Mosquitoes only 50 miles north of Cairo at the southern are among the worst nuisances of the out- tip of Illinois. Psorophora discolor, varipes, of-doors and prevent enjoyment of recrea- and cyanescens, and Megarhinus septentri- tional facilities by many people seeking exer- onalis are southern species which often cise and relaxation. occur in the southern eighth or fourth of Disease-transmitting mosquitoes are the Illinois and sometimes sparingly north of sole vectors of malaria in human beings. that. Malaria is an endemic disease in southern Aedes aegypti is another southern mos- Illinois. Only 50 miles to the south of Illi- quito that has been taken in the St. Louis nois, in the Mississippi River valley, occurs area and southward. Apparently it is unable one of the high density areas of this disease to maintain itself there and occurs only as a in eastern North America. Anopheles quad- temporary adventive during favorable years. rimaculatus is considered the only impor- The southern house mosquito, Cu/ax tant mosquito species capable of transmit- quinquefasciatus, which has been taken in ting the disease in Illinois. some numbers in southern Illinois, occasion- Several other human diseases, such as ally extends northward at least as far as yellovv fever, filariasis, and dengue, are Urbana. Present collection data are far transmitted by certain species of mosquitoes from conclusive but suggest that unfavor- that occur in Illinois. However, recent out- able winters push back the range of this breaks of these diseases are so far removed species and that it migrates northward again geographically from Illinois, or the known during a succession of favorable years. mosquito vectors are so rare in this state, Perhaps our most unusual record is that that the diseases are not considered a serious for Aedes aurifer, a northern and eastern threat to Illinois citizens at the present time. mosquito for which we have only one Illi- Public health workers have pointed out nois record, from the extreme southern tip that a number of the service men returning of the state. Almost as unusual is the occur- from areas in the Pacific and Oriental rence of the northern Aedes cinereus in the regions where many insect-borne diseases same locality. Presence of these northern occur will have been infected with these species in southern Illinois illustrates a tend- diseases. It is entirely possible that, upon ency, which has been noticed in several other returning home, the men may be a source insect groups, for occasional northern spe- from which mosquitoes may become infected cies to occur in or near the Mississippi River with some of the tropical diseases and trans- region south of the main body of their range. mit them to other persons resident in the same locality. There is little possibility of ECONOMIC IMPORTANCE knowing when and where such situations will arise. At the present time this problem Mosquitoes cause an economic loss both seems to resolve itself into one of early as nuisances and as disease carriers. detection and accurate diagnosis of the dis- The nuisance category includes all those eases by local medical authorities. species that inflict painful bites but that are Up to the present time measures insti- not known to carry diseases. Most impor- tuted against mosquitoes in Illinois have tant in this group are the various species of been directed toward abatement of nuisance Aedes and Psorophora; in cities and towns, species or toward control of the malaria species of Culex are of prime importance. vector, A nopheles quadrimaculatus. Mosquitoes in the nuisance group inflict financial loss in various ways. In some sec- CONTROL CONSIDERATIONS tions they restrict the vacation season, with subsequent loss of patronage to resort estab- Control measures require consideration lishments. They attack domestic animals as individual problems in each community and fowls and, when in large numbers, cause or locality. In different localities different loss of weight and health. It has been esti- species of mosquitoes are encountered, bring- mated that 500 mosquitoes will draw one- ing into the control problem the treatment twentieth of a pint of blood per day from of different habitats, and involving differ- an exposed animal. Sometimes mosquitoes ences in number and seasonal timing of 10 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Jr/. 1 mosquito generations. Vagaries of precipi- Larvae tation or flooding frequently require rapid and unexpected changes in control plans. A white enameled dipper, about 6 inches Control measures, to be both economical in diameter, is the most convenient utensil and thorough, must be based on data for collecting mosquito larvae. It may be obtained by a collecting and identification used to dip up larvae from ponds and open program. It is wasteful to attempt control water. The larvae can be removed from measures of every water surface within an the dipper by one of two methods: (1) by area, because many bodies of water (and pulling them into a wide-mouth medicine frequently the most extensive ones) do not dropper and then discharging them into a serve as breeding places for mosquitoes. vial of preservative or into a rearing cap- Before actual control measures are planned, sule or (2) by pouring the contents of the therefore, larval collections should be made dipper slowly onto a cloth strainer, picking that will serve as a guide to the areas to be the larvae off the cloth with forceps, and treated. transferring them to a preservative or to a To check the efficiency of control opera- rearing vial. Hairs of the larvae are easily tions, it is necessary to supplement larval knocked off or the larvae mutilated in other collections with biting records and adult ways if the transfer is made carelessly. collections throughout the season. These Alcohol makes a satisfactory preserva- should include light trap collections and col- tive; 80 per cent alcohol is strong enough if lections from resting stations. the larvae are transferred to it with forceps. The persistence of adult mosquitoes in a If a medicine dropper is used to transfer control area (shown by collections and biting the larvae, a few drops of water will be dis- records) may indicate that breeding places charged into the preservative with each within the area have been overlooked or larva, and a stronger solution of alcohol that mosquitoes are coming in from sur- should be used. Not more than two live rounding territory. After overlooked sites larvae should be placed at the same time have been eliminated, collection and identifi- in a single vial. If many thrash around in cation of larvae from breeding places in the vial, they knock the hairs off each other. surrounding territory will indicate addi- As many as 10 larvae may be put in a three- tional places which should also be treated. dram vial, but they should be put in one at When adult mosquitoes are identified as a time ; the second and succeeding larvae to species, facts about them, fundamental in should not be put in until the first and others controlling them, can readily be ascertained: have died. The most satisfactory way to (a) the types of situations in which larvae kill a larva desired for a specimen is to place should be sought and (b) breeding habits, it in a separate killing vial and transfer it to that is, whether the mosquitoes are annual, a stock vial after it has died. intermittent, or persistent breeders. Such If larvae are handled in a vial only par- information is useful in searching out places tially filled with preservative, they will where control treatments must be applied jounce around, with a consequent loss of and determining whether the treatments hairs and tufts. If the specimens are in a need to be applied only once a year for vial that is filled with preservative, without annual breeders, following rains or floods a single air bubble in it, they will move only for intermittent breeders, or at regular slowly, no matter how violently the vial is intervals for persistent breeders. agitated, and suffer no damage. To preserve larvae in this way, the follow- COLLECTING AND ing procedure is recommended. Put the dead PRESERVING larvae in a small shell vial; put this vial, open end up, in a larger vial containing Mosquitoes, both adults and larvae, are alcohol above the top of the shell vial. Now so delicate that their hairs and scales, upon pick up a plug of cotton with a pair of for- which identification is based, are readily ceps, soak the cotton with alcohol, and plug broken or rubbed off by careless handling. the open end of the shell vial with the cot- For this reason it is necessary to use great ton under the alcohol. Then take the shell care in the procurement of material and in vial out of the larger vial, put it in again its subsequent handling and preparation for plugged end down, and stopper the large study. vial, fig. 10J.

August, 1947 Ross: MOSQUITOES OF ILLINOIS 11

where in the vehicle used for transport that they will not tip. Sweeping.—Sweeping around vegetation does not net good study specimens of females, but it is valuable in collecting males. Fre- quently the males are present around a pond after all the immature stages in it have matured. Collections of males often give an accurate clue as to the species that develop in the pond, and their proportionate populations. The type of sampling done by sweeping vegetation is especially valuable in scout- ing temporary pools. A standard sweep net can be used, and the males picked out of the net with an aspirator. If the collector desires to obtain, by using a net, female mosquitoes that are in good condition, it is Fig. 10.-4, vial with inner vial contain- advisable that the net bag be made of very ing mosquito larvae. B, mosquito mounted on fine, light material. For routine collections crimped point and genitalia in microvial with of males, it is more practical to use a heavy pin through cork. bag that will withstand the abuse involved in hitting shrubs, thick herbage, and the like. The plug is prepared by rolling a small Light Traps.—A standard light trap used piece of cotton between the fingers until it is fairly hard; after a little practice, a plug can be gauged that will fit the shell vial tightly but that is not so large that the vial will be broken when the plug is forced in. For storage, the larger vial should be kept well filled with alcohol; no evaporation will occur from the inner vial until the alcohol in the outer one is almost gone.

Adults

There are three principal methods of collecting adult specimens: (1) by placing a killing tube over them as they sit in natural resting places or as they alight to bite, (2) by sweeping them from vegetation around their breeding places or sweeping them in the air as they swarm in mating flights, and (3) by attracting them to light traps. Killing Tube.—Collecting adults with a killing tube calls for the same careful individual attention as does collecting larvae. Scales of the adults rub off very easily. For this reason, a tube with a strong killing agent should be used and only one live mosquito should be placed in a tube at one time, never more than 6 to 10 dead ones. It is wise to carry several boxes with loose, rumpled cellucotton in the bottom and to transfer to these each dead mosquito from a killing tube. These boxes, which should have tight- Fig. 11.—Light trap. (Photograph by cour- fitting lids to prevent accumulation of dust tesy of Bureau of Entomology and Plant Quar- on the specimens, should be so placed some- antine, U.S.D.A.) 12 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1 for mosquitoes at the present time is the Larvae New Jersey light trap, fig. 11. This attracts mosquitoes by means of a low wattage elec- In most instances it is satisfactory to pre- tric light bulb and is provided with a fan serve larval material in alcohol. Diagnos- that blows them into a killing jar. The tic characters in most groups are seen read- light bulb and fan are fastened to the inside ily on specimens in fluid. of a large cover, which sheds rain, and a For detailed studies of pecten and comb funnel is below the fan, fastened to three scales, a permanent mount is desirable. The legs that support the trap when it is placed larva should be dehydrated by being run on the ground. The standard trap has a through the alcohols to 95 per cent, cleared handle on the top, so that in the field it may in benzol or cedar oil, and then mounted in be hung in a tree or from some other sup- Damar balsam. Each larva with an air tube port. Mosquito specimens collected in this should be cut through the seventh abdomi- type of trap are usually in fairly good con- nal segment and the anterior portion dition. Occasionally a swarm of beetles mounted with the dorsum up and the poste- will be attracted to the light and blown into rior end with the left side up. This mount- the killing jar. The beetles will crawl and ing will allow the study of the largest num- thrash through the collection and mangle ber of characters to best advantage. Pieces the mosquitoes. of broken slides should be placed around Individual catches from each trap should the specimen in such a way that they prevent be placed, while still pliable, between layers the cover slip from flattening and distorting of cellucotton in pill boxes. These layers the specimen. When the air tube is flat- should be thick enough to dry the insects tened, its proportionate length to width thoroughly; otherwise mold may engulf the becomes greatly distorted and cannot then collection and render it useless for study. be used as an accurate guide for identifica- At the top of the pill box enough extra cot- tion. ton should be added so that, when the lid is put on, the contents will be held firmly, hilt Adults not so tightly as to crush the specimens. The container may then he transported with- Material brought in from the field should out injury to the contents. A collection of be mounted for study. A very satisfactory pill boxes having different diameters and method of mounting is to glue the insects cardboard boxes 2 by 3 inches to 3 by 5 on card points. If the end of the point is inches gives a good selection for handling crimped down quite a distance, and moder- catches of various sizes. These containers ately thin cellulose cement is used for glue, should be packed with cotton in a larger box a neat mount can be made with the dorsum if shipped by mail. of the specimen uppermost. Before being pinned, adult specimens should be relaxed Labeling for a short time. There is a tendency for the specimen to become greasy if relaxed No matter what type of collection is made, too long, and care must be observed regard- each container, whether box, tube, or vial, ing this point. Full data labels should be should be labeled with station number, put on every specimen. locality, date of collection, and name of col- Critical study of adult material frequently lector. If the collection is of adults, note requires detailed examination of the geni- should be made of whether each container talia. A preparation of the genitalia may represents a biting record, a catch in a rest- be made as follows: snip or break off the ing station, a light trap catch, or a sweep- posterior half of the abdomen and place it ing record. in a vial of 5 per cent caustic potash or caustic soda solution; heat the vial in a boiling STUDY TECHNIQUES water bath for about 5 minutes; remove the preparation from the caustic solution and When the mosquito material, either larval place it in distilled water; press it gently or adult, is brought to the laboratory for with a needle to squeeze out dislodged vis- study, the same care must be exercised in its cera and brush it carefully to clean off further preparation as was expended in its lodged scales or dirt. Transfer the prepa- collection. ration to fresh, distilled water, leave it zlugust, 1947 Ross: MOSQUITOES OF ILLINOIS 13 there for 15 minutes to an hour, and then pupa will mature in 3 or 4 days, and the transfer it to 80 per cent alcohol that is very adult will emerge. It is advisable to have weakly acidulated with acetic acid. After some sticks or rumpled paper towel in the leaving it in this solution for a few minutes, top of the dry part of the container so that transfer it to a drop of glycerin in a well the adult may rest there and harden for 2 mount on a slide. The preparation is then or 3 days before being killed. Adults killed ready for microscopic examination. For immediately upon emergence will shrivel. preservation, place the preparation in a very Frequently the adult can be transferred into small vial, about 4 by 10 mm., which has a a second container without free water and droplet of glycerin about 3 mm. deep in the kept there for a few days to avoid the possi- bottom. Cork the vial and then push the bility of its drowning and disintegrating in pin, on which the insect is mounted, through the water. The pupal skin, larval skin, and the cork sidewise, as in fig. 10B. adult should be preserved and mounted In the case of heavily sclerotized genitalia, according to usual methods, and specimens especially those of many zledes, it is neces- of the same rearing associated by means of a sary to use a caustic solution of 10 or 15 per distinctive accession number system. A con- cent instead of 5 per cent. venient system is to use a lot number for For making large numbers of genital each collection and a letter for each indi- preparations simultaneously, it is conveni- vidual of this collection. For example, speci- ent to use a battery of small vials of cold mens from collection No. 157, bear the caustic solution. Good results with the accession designations 157C, 157D, 157E, more heavily sclerotized genitalia, such as etc.; the adult bearing the label 157C is those of zledes and Psorophora, can be associated with a larval skin and a pupal obtained with about 12 hours of clearing in skin also bearing the accession designation cold 5 per cent caustic solution. For the 157C. No other specimen or skin in the more weakly sclerotized preparations, such collection has on its label 157C. With this as those of Culex, 5 or 6 hours of clearing method, it is possible to avoid getting the are usually ample. skins and adults of different rearings mixed. It is often necessary to tease apart vari- Every skin and adult should be labeled ous structures of the genitalia in order to promptly and clearly. see certain characters. For this purpose fine needles can be made from 00 insect pins. Group Rearings Snip off the head of the pin; then, holding the pin near the blunt end with pliers, force In order to secure large numbers of study it bit by bit into a wooden handle whittled specimens in good condition, group rearings to suit the user. Large match sticks make are of much use. Larvae may be placed in fairly good handles for small needles. a large tube or mason jar and fed until they transform to pupae. For small cultures of REARING less than 20 specimens, a cap vial about 11/2 inches in diameter and 2 or 3 inches long Rearing is a necessary part of the mos- is very satisfactory. After a culture has quito study program. There are many in- pupated, the container should be placed in a stances in which the larvae, or the males or large dry-battery jar or cage having a tight females, of two species cannot be differenti- muslin top, and a liberal amount of crum- ated, so that for final identification it is nec- pled paper toweling placed in the bottom. essary to have associated larvae and adults. The small container can be fastened upright Two types of rearings are useful, individual on the inside of the large container by adhe- rearings and group rearings. sive tape. After adults begin to emerge, water can be squirted through the muslin Individual Rearings top onto the paper toweling, care being taken not to bathe the adults. This water A single larva is isolated in a vial or dish, will prevent desiccation of the adults and about half full of water, and food is added their premature death. In 2 or 3 days the until the larva matures. When it molts to adults will harden satisfactorily, and the form a pupa, its cast larval skin is immedi- entire cage can be treated with a fumigant ately preserved in alcohol or mounted on a to kill them. They may then be picked out slide. At ordinary room temperatures the of the cage and mounted. 14 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

Larval Food consist chiefly of a proboscis (which may be either short and flabby, or elongate and If larvae are collected when almost ready forming a beak) and a pair of maxillary to pupate, a supply of the water in which palpi; the palpi are referred to in this report they have been breeding and some of the as "palps." The legs are long and spindly. organic matter from the bottom of the same The wings are fairly large; radial sector is pond will provide ample food to carry them 3-branched and Media is 2-branched; the to full development. If, however, they are branches of radial sector are either nearly collected at an earlier stage, it is necessary straight or only slightly curved. The family to add food. The safest type of food is is divided into two subfamilies, the Chaobo- fresh material from the bottom of a pond; rinae, or non-biting mosquitoes, and the Culi- this may be added to the rearing containers cinae, the true mosquitoes. An adult of the every 2 or 3 days. If this food cannot he Chaoborinae is readily distinguished from obtained conveniently, various prepared all adult Culicinae because it does not have foods, such as crumbled yeast, powdered dog a beak; each adult of the Culicinae has a biscuit, moldy corn, and gold fish food can well-developed beak or proboscis. The larvae be substituted. Because there is great danger of some C7haoborinae, however, might he that these concentrated foods will putrefy readily confused with the larvae of true in the water, resulting in bacterial growth mosquitoes. that will kill the mosquito larvae, they should be used in minute quantities. Terminology

Temperature, Aeration, and Sunlight Many special terms are employed for distinctive parts of both adults and larvae of If the rearing is done indoors in hot the mosquitoes, and these terms are used weather, death of the larvae may result throughout the keys and descriptions. Fig. from too high a temperature or from insuffi- 12 is labeled to identify these distinctive cient aeration. Larvae that normally live parts of the larvae. Special parts of the in a cold water environment should be kept relatively cold. It is desirable to keep jars containing such larvae in a running water bath. This will generally keep the temperature of the rearing medium below 75 degrees F. Good ventilation is necessary for indoor ./ rearing of Anopheles larvae. Satisfactory results are obtained with these larvae by using rearing containers nearly filled with water and placed near or in an open win- dow; for adult emergence the pupae should be transferred to containers with 2 or 3 inches of air space above the water. Some exposure to sunlight gives good results, but in the heat of summer this exposure must be short to avoid overheating the water.

CLASSIFICATION

Mosquitoes belong to the order Diptera, or two-winged flies and to the family Culi- cidae. This family is characterized by the following adult structures: antennae, figs. 32-38, filamentous and slender, with 15 segments, the first 2 forming the base and the last 13 forming the slender thread. Each segment has a whorl of hairs, which in the males are extremely long. The eyes are Fig. 12.—Larval diagram, Culicinae. (After large and conspicuous. The mouthparts King, Bradley, & McNeel.) August, 1947 Ross: MOSQUITOES OF ILLINOIS 15

13.—Anopheles larva. Left figure, dorsal view of entire larva ; upper right figure, details of thorax; lower right figure, apex of abdomen, lateral aspect. (After Ross & Roberts, by courtesy of American Entomological Society.) adults arc identified on diagnostic draw- 1937. The Mosquitoes of Minnesota, ings where they appear in the text associated by William B. Owen. with the keys. Distinctive structures of 1939. The Mosquitoes of the Southeast- Anopheles larvae are shown in fig. 13. ern States, by W. V. King, G. H. Bradley, and T. E. McNeel. Literature 1941. The Mosquitoes of Arkansas, by Stanley J. Carpenter. Additional information about mosquitoes, 1942. The Mosquitoes of Oklahoma, by especially species not contained in this report, L. E. Rozeboom. will be found in the general mosquito reports 1944. The Mosquitoes of Wisconsin, by listed below. Additional information con- W. E. Dickinson. cerning these reports is given in the section 1944. Handbook of the Mosquitoes of "Literature Cited." Papers of more limited North America, by Robert Mathe- scope are mentioned later in the text in ref- son. erence to particular genera or species. 1944. The Mosquitoes of Texas, by Texas State Health Department. 1928. The Mosquitoes of the Americas, 1946. The Mosquitoes of the Southern by Harrison G. Dyar. United States, by Stanley J. Car- 16 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

penter, Woodrow W. Middlekauff, merman for the many original drawings and Roy W. Chamberlain. which she made for this report. Various individuals and organizations Material Studied were extremely kind in either loaning drawings and cuts for use in this bulletin or in The major part of the material on which giving permission to reproduce illustrations this study is based was collected by staff appearing in their publications. On this score members of the Insect Survey Section, Illi- I am especially indebted to Professor nois Natural History Survey. Various other Robert Matheson and the Comstock Pub- persons or organizations contributed much lishing Company ; the American Entomolog- valuable material, and I am greatly indebted ical Society; the Entomological Society of to them for permission to use their records Washington; the Bureau of Entomology and in this paper. T. Lye11 Clarke, Des Plaines Plant Quarantine, U. S. Department of Valley Mosquito Abatement District, Lyons, Agriculture ; and the Malaria Control in Illinois, and M. A. Dobbs and J. M. Gilbert, War Areas, U. S. Public Health Service. East St. Louis Health District, contributed extensive material. I wish to express KEY TO SUBFAMILIES my appreciation to officials of the Chicago Natural History Museum, who allowed LARVAE me to study their mosquito collections; indi- 1. Antennae arising close together on a mesa] vidual records from their material are raised area or protuberance of the head, marked in this paper with the initials cm. fig. 14 ...... Chaoborinae In addition, I am greatly indebted to offi- Antennae arising at sides of head, figs. 12, 13 ...... 2 cials of the U. S. Public Health Service and the Illinois State Department of Public 2. Anal segment with a sclerotized ring or plate, figs. 17-20; antennae without long, Health for permission to use their extensive prehensile hairs ...... Culicinae records of Illinois mosquitoes; these records Anal segment without either a sclerotized are indicated in this paper by the abbrevia- ring or plate; antennae with long, prehen- tion USPHS. sile hairs (Mochlonyx and Eucorethra), figs. 15, 16 ...... Chaoborinae Acknowledgments ADULTS 1. Proboscis elongate, figs. 32-38, many times I wish to express my gratitude to several longer than depth of head ...... Culicinae workers who were kind enough to check Mouthparts forming only short submr_mt- keys and to give advice on many questions branous lobes which are no longer than which have arisen during the progress of depth of head ...... Chaoborinae this report. Captains C. F. Gerlach and F. Earle Lyman of the U. S. Public Health Service were very helpful in these matters. I am especially indebted to Dr. Alan Stone, U. S. Bureau of Entomology and Plant Quarantine, who was of the utmost assist- ance regarding the taxonomic problems which arose time and again. I wish to thank also the officers of the U. S. National Museum for the loan of considerable study material of critical species, especially larval material of rare Aedes species. Dr. C. 0. Mohr, Dr. B. D. Burks, and Mr. G. T. Riegel were very active in the earlier years of this project, 1938-1942, in collecting and rearing material. In 1944 Fig. 14.—Head of larva of Corethrella. and 1945, Dr. Kathryn M. Sommerman and Dr. Milton W. Sanderson aided in this Fig. 15.—Larva of Mochlonyx cinctipes. work. Dr. Sommerman and Mr. Riegel did ( Redrawn from Matheson.) the larger part of the rearing in the labora- Fig. 16.—Larva of Chaoborus punctipennis. tory. I am greatly indebted to Dr. Sow- (Redrawn from Matheson.) „lugust, 1947 Ross: MOSQUITOES OF ILLINOIS 17

Subfamily CHAOBORINAE /boles inzplacabilis (Walker) Aedes mitchellae ( Dyar) The adults of this subfamily are midge- Aedes nigromaculis (Ludlow) like ; their bodies usually are hairy but with- Aedes punctor (Kirby) out scales. Four genera comprise the North Aedes sollicitans ( Walker) American fauna of the subfamily. Of these, Aedes spencerii ( Theobald) Chaoborus, Corethrella, and Mochlonyx Aedes sticticus ( Meigen) occur in Illinois; the fourth genus, Eucore- Aedes stimulans ( Walker) thra, is widely distributed north of Illinois Aedes thibaulti Dyar & Knab but has not yet been taken in the state. Aedes triseriatus (Say) Larvae of Chaaborus, fig. 16, have no air Aedes trivittatus ( Coquillett) tubes. Larvae of the other three genera Aedes vexans ( Meigen) have either air tubes (illochlonyx and Core- Anopheles barberi Coquillett thrella) or spiracular plates of the Anoph- Anopheles crucians Wiedemann eles type (Eucorethra); in these genera Anopheles punctipennis (Say) the larvae are predaceous and in gen- Anopheles quizzirimaculatus Say eral appearance resemble those of some nopheles walker Theobald biting mosquitoes. Culex apicalis Adams A synopsis of the North American species, Culex erraticus ( Dyar & Knab) together with keys and illustrations, is pre- Culex peccator Dyar & Knab sented by Matheson (1944). Culex pipiens Linnaeus Culex quinguefasciatus Say Subfamily CULICINAE Culex restuans Theobald Culex salinarius Coquillett To date, 10 genera of this subfamily, rep- Culex tarsalis Coquillett resenting the true mosquitoes, have been Culiseta inornata ( Williston) taken in Illinois. It should be emphasized Culiseta morsitans ( Theobald) that this mosquito group includes all the Mansonia perturbans ( Walker) Culicidae with well-developed beaks, many Megarhinus septentrionalis Dyar & Knab species that bite, and in addition a few spe- Orthopodomyia alba Baker cies that do not bite. Orthopodomyia signifera ( Coquillett) The subfamily Culicinae is frequently Psorophora ciliata ( Fabricius) divided into two tribes, the Anophelini, in- Psorophora con fuels ( Arribalzaga) cluding in the Illinois fauna only Anopheles, Psorophora cyanescens (Coquillett) and the Culicini, including the other nine Psorophora discolor (Coquillett) Illinois genera. However, the subfamily is Psorophora ferox ( Humboldt) sometimes divided into a large number of Psorophora horrida ( Dyar & Knab) tribes. Since the final solution of this prob- Psorophora howardii Coquillett lem in taxonomy will require a study of the Psorophora varipes ( Coquillett) world fauna, the most practical solution for Uranotaenia sapphirina ( Osten Sacken) the present report has been to avoid segre- Wyeonzyia smithii ( Coquillett) gation into tribes and to treat the subfamily as a single unit. KEY '1 0 GENERA

Mosquitoes of Illinois LARVAE 1. Eighth segment with a flat spiracular plate, net/es aegypti ( Linnaeus) but no air tube, fig. 13..1. Anopheles A edes aurifer (Coquillett) Eighth segment with an air tube, figs. Aedes canadensis (Theobald) 17-20 ...... 2 Aedes cinereus Meigen 2. Air tube short, with some of its sclerites at Aeries dorsalis ( Meigen) the apex forming long stout spurlike Aedes dupreei ( Coquillett) processes, fig. 18 ...... 5. Mansonia Aedes excrucians ( Walker) Air tube without stout processes, its apical sclerites flat or conical, figs. 17, 19, 20 edes fitchii ( Felt & Young) 3 Aedes flavescens 3. Ventral brush of anal segment represented Aedes fulvus pal/ens E. S. Ross by only an apical pair of double hairs, iedes grossbecki Dyar & Knab fig. 20 ...... 4. Wyeomyia 18 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 1 ol. 24, 'ht. 1

Larval parts: A, apex of abdomen; B, dorsum of head.

Fig. 17.—OrthOodomyia signifera. Fig. 19.—Megarhinus septentrionalis. Fig. 18.—Mansonia pertzerbans (the air tube Fig. 20.—W yeomyia stnithii. Note ventral only.) (After King, Bradley, & McNeel.) brush reduced to only four long hairs. ilagust, 1947 ROSS: MOSQUITOES OF ILLINOIS 19

Ventral brush of anal segment consisting species, wing length under 3.5 mm.... of several tufts, figs. 17, 19 ...... 3. Uranotaenia 4. Anal segment with sclerotized plate not 3. Mesoscutellum with apical margin evenly meeting ventrad, figs. 102-105. Many rounded, the setae arranged evenly along species of 9. Aedes it, fig. 24; male with clavate palps, fig. Anal segment completely ringed by sclero- 37, and female with palps as long as tized plate, fig. 17 ...... 5 beak, fig. 38 ...... 1. Anopheles 5. Air tube cylindrical and without pecten, Mesoscutellum with apical margin incised figs. 17, 19 ...... 6 to form a mesal lobe and two lateral Air tube either fusiform, fig. 175, or with lobes, with the setae grouped on these a pecten, figs. 75, 98, 172 ...... 7 three lobes, fig. 25; male palps not cla- 6. Abdominal segments 3-7 with three spine- vate and female palps short, fig. 35...4 bearing sclerotized plates on each side, 4. Mesonotum with a mesa] line of short fig. 19A; head quadrate, with stout setae and scales, and with a wide, pol- mouth brushes and only a few single ished bare area along each side of the dorsal setae, fig. 19B. .. .2. Megarhinus mesal line, fig. 26; hind femur with a Abdominal segments 3-7 without lateral tuft of projecting scales at apex, fig. 28. plates, sometimes segments 6 and 7 with Large species of 10. Psorophora dorsal saddle, fig. 17A; head oval, with fine bushy mouth brushes and with most Mesonotum without linear, polished bare of the dorsal setae multiple, fig. 17B areas; hind femur with only a few pro- ...... 6. Orthopodomyia jecting hairs at apex, fig. 30 5 7. Comb teeth situated on the posterior mar- 5. Hind tarsi with one or two segments en- gin of a large sclerotized plate that cov- tirely white, the remainder entirely blue ers most of the eighth segment; head or black. A few species of with four stout black spines ; fig. 72 ...... 10. Psorophora ...... 3. Uranotaenia Hind tarsi either with some segments Comb teeth either on a small, poorly de- banded, fig. 29, or all segments nearly fined plate, fig. 172, or not on a plate; the same color 6 head with slender hairs, no stout spines, 6. Hind tarsi with wide or conspicuous bands fig. 74 ...... 8 of white on most segments, fig. 29 ...... 7 8. Air tube with a single pair of ventral Hind tarsi with no bands or with only tufts situated at base, figs. 74, 75 inconspicuous ones 13 ...... 7. Culiseta 7. Second, third, and fourth tarsal segments Air tube either without ventral tufts, or each with a narrow white band at each with tuft near middle or apex, figs. 98- end, fig. 29 ...... 8 101, or with air tube having several Second, third, and fourth tarsal segments pairs of tufts, figs. 80-85 ...... 9 each with a white band at base only, 9. Air tube with several pairs of ventral figs. 127-131 ...... 10 tufts of which some may be represented 8. Beak black, with a definite white band in by single long hairs, figs. 79-85 middle, as in fig. 35. The species tar- ...... 8. Culex salis in 8. Culex Air tube with only a single pair of ventral Beak not banded, either all black, or mot- tufts, or with none 10 tled, or black with rows of white scales 10. Ventral brush of anal segment having sev- along its entire length 9 eral tufts that arise out of the sclerotized 9. Mesonotum either without white lines, or ring, figs. 172-174 ...... 10. Psorophora generally cream in color as in fig. Ventral brush of anal segment with all 119.

tufts situated posterior to sclerotized A few species of 9. Aedes nearly black, with a series of ring, fig. 111. Some species of ..9. Aedes Mesonotum white lines as in fig. 27 ...... ADULTS 6 Orthopodomyia 1. Fork of R2, close to margin of wing, cell Post-spiracular area entirely bare; hairs R2 only half length of its petiole, 10. on disc of long, abundant, fig. 21 ...... 2 mesonotum and erect, fig. Fork IL, much farther from margin of 39 ...... 5. Mansonia area with bristles or a wing, so that cell R., is as long as its Post-spiracular patch of scales; hairs on disc of prono- petiole, fig. 22 ...... 3 fig. 41....11 2. Beak curved almost into a quarter circle, tum much more appressed, palps of both sexes very long, those of 11, Outer faces of hind femora in general female massive, figs. 33, 34; large spe- dark but each with a transverse band of cies, wing length 6.5 mm...... white scales near apex, fig. 31. A few ...... 2. Megarhinus species of 10. Psorophora Beak only slightly curved, palps of both Outer faces of hind femora without such sexes short and abortive, fig. 32; small bands 12

20 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

12. Wings with either Costa banded with dark scaled, or the two types of scales white-scaled areas and black-scaled mingled in a salt-and-pepper, patternless areas, or anal vein white scaled for mixture. Some species of 9. Aedes basal two-thirds with apical portion 13. Mesonotum covered with a close mat of black scaled. A few species of blue-black scales, with bristles only 10. Psorophora around periphery; fork of R21-3 basad of Wings either almost uniformly white or fork of M,.+2, fig. 22 4. Wyeomyia

Adult Parts

Fig. 21.—Uranotaenia sapphirina, wing. Fig. 31.—PsoroPhora confinnis, hind femur. Fig. 22.—W yeomyia smithii, wing. Fig. 32.—Uranotaenia sapphirina, male Fig. 23.—A edes vexans, wing. head, septentrionalis, Fig. 24.—Anopheles guadrimaculatus, meso- Fig. 33.—Megarhinus male head. noturn. Fig. 34.—M egarhinus scptentrionalis, female Fig. 25.—A edes vexans, mesonotum. head. cilia/a, Fig. 26.—Psorophora mesonotum. Fig. 35.—A edes sollicitans, female head. Fig. 27 .—Orthopodomyia signifera, meso- Fig. 36.—Orthopodomyia signifera, female noturn. head. Fig. 28.—Psorophora ciliata, hind leg. Fig. 37.—Anopheles guadrimaculatus, male Fig. 29.-4 edes canadensis, hind leg. head. Fig. 30.—Psorophora varipes, portion of hind Fig. 38.—Anopheles guadrimaculatus, fe- leg. male head. Jugust, 1947 Ross: MOSQUITOES OF ILLINOIS 21

Adult Thorax, Lateral Aspect. Abbreviations: pa, pronotal bristles; ps, post-spiracular bristles or scales; s, spiracle; sb, spiracular bristles.

Fig. 39.—Manse ha perturbans. Fig. 41.—Psorophora confinni;. Fig. 40.—Culiseta inornata. Fig. 42.-21edes stimulans.

Mesonotum With several series of erect Without spiracular bristles; post-spiracu- bristles extending above scales on disc, lar area with hairs or hairs and scales, fig. 42; fork of 122-,2 at about same level fig. 42. Many species of ... Aedes as that of M,2, fig. 23 ...... 14- 14. Mesonoturn either with broad lateral MALE GENITALIA bands or areas of white or cream scales, 1. Dististyle with a contorted mass of figs. 115, 120-123, or almost entirely branches, fig. 46 ...... 4. Wyeomyia covered with cream scales 15 Dististyle either unbranched, fig. 43, or Mesonotum mostly dark scaled, at most with only one or two simple lobes, figs. with a scattering of light scales, or with 133, 178 ...... narrow weak lines of them 16 2. A pair of subcylindrical arms (claspettes) 15. Hind tibiae enlarged and shaggy toward arising from dorsum of capsule, and apex, with setae not longer than width tipped with a sclerotized filament, figs. of tibia at apex, fig. 30; spiracular 136-158. Most species of ....9. Aedes bristles usually present, fig. 41. A few Claspettes absent, platelike, fig. 70, or each species of 10. Psorophora tipped with a cluster of spines, fig. 177 Hind tibiae slender to apex, not shaggy, 3 often with a scattering of setae longer 3. Dististyle bib bed, its mesal margin bear- than width of tibia at apex, figs. 29, ing a long hook and a large membranous 125, 126; spiracular bristles absent. lobe, fig. 178. The species howardii in Many species of 9. Aedes 10. Psorophora 16. Post-spiracular area bare, and spiracular Dististyle without an accessory membra- bristles lacking, as in fig. 39 ...... nous lobe 4 ...... 8. Culex 4. Basisty-le with an apico-mesal shoulder Thorax either with post-spiracular area bearing a cluster of specialized., blade- having bristles or scales, fig. 42, or like or spatulate spines, which are fre- spiracular bristles present, fig. 40, or quently complex in structure, figs. 88-95 both 17 8 Culex 17. Spiracular bristles present; post-spiracular Basistyle either without an apical shoul- area sometimes with scales but never der, or the shoulder bearing only nar- with hairs, fig. 4-0 ...... 7. Culiseta row spines 5 22 ILLINOIS NATURAL HISTORY SURVEY BULLETIN ol. 24, Art. 1

5. Apex of basistyle continuing as a pointed Claspettes absent or platelike, fig. 70, dis- lobe beyond insertion of dististyle, fig. tistyle of various shapes ...... 135. The species rinereus in ...... 8. Basistyle with a stout peglike rod on mesal ...... 9. Aedes face near middle; dististyle with apical Dististyle situated at apex of basistyle, half very wide, its apical seta forming fig. 43 ...... 6 a stout spurlike tip, fig. 43 ...... 6. Dististyle with a pointed lobe projecting ...... 5. Mansonia beyond apical spur, fig. 133. The spe- Basistyle frequently with one or more cies vexans in ...... 9. Aedes stout setae on mesal face, but never with Dististyle with apical style terminal, fig. a rodlike structure; dististyle either not 45, or apex round, fig. 47, or truncate, enlarged at apex or with a peglike or fig. 180 ...... 7 hairlike apical seta, figs. 45, 47 ...... 9 7. Claspettes each with a stalklike base, and 9. Basistyle short and ovate, with a pair of with a comblike cluster of spurs or setae large, stout spines dominating the ven- at apex, figs. 177, 179-182; dististyle tral aspect of the basal portion, fig. 70 sinuate, fig. 177, or bulbous, figs. 179- ...... 1. Anopheles 182. Most species of. . .10. Psorophora Basistyle either long and slender, fig. 45,

Male Genitalia

Fig. 43.—Mansonia perturbans, ventral as- Fig. 45.—Orthopodomyia signif era, ventral pect, and lateral aspect of dististyle. aspect. Fig. 44.—Uranotaenia sapphirina; A, ven- Fig. 46.—Wyeomyia smithii; A, ventral as- tral aspect, with lateral aspect of dististyle; pect; B, lateral aspect. B, mesal aspect of clasper, with mesosome and Fig. 47.—Megarhinus sefitentrionalis, ventral other mesal structures removed. aspect.

ugust, 1947 Ross: MOSQUITOES OF ILLINOIS 23

or without a pair of isolated stout spines 12. Base of basistyle with a mesal, arcuate on basal portion of ventral aspect, fig. pad bearing a crown of stout spines; 44 10 dististyle cylindrical, with apical spine 1 1). Ninth tergite forming a large bib bed just before apex, fig. 47..2. Megarhinus sclerotized plate whose lateral lobes are Base of basistyle without a mesal pad ; nearly as long as the basistyle, fig. 44.. dististyle tapering toward apex, apical 3 Uranotaenia spine issuing from tip, fig. 134. The Ninth tergite forming at most a plate as species aegypti in 9 Aedes wide as in fig. 47 11 13. Apical spine of dististyle double, each ray H. Apical seta of dististyle single, slender, short and stout ; mesosome without lat- and pointed at tip, figs. 47, 134 12 eral teeth at apex, fig. 78...7. Culiseta Apical seta of dististyle short and either Apical spine of dististyle cone shaped, divided, fig. 78, or truncate at tip, fig. wide and truncate at apex, and with 45 -■ 3 what appears to be a minute fringe

9 10 48 Atio 49

48 A

49 A 49 48 C

iweg• - V 52 A 51 A –

53 C 4 55 B

53 B

54B ' 56 B 57 B

Female Genitalia: A, lateral aspect: B, ventral aspect; C, dorsal aspect. Abbreviations: c, cercus; p, postgenital plate; i, insula plate.

Fig. 48.—.//nopheles quadrimaculatus. Fig. 53.—Culiseta inornata. Fig. 49.—Uranotaenia sapphirina. Fig. 54.—Culex restuans. Fig. 50.—Wyeomyia smithii. Fig. 55.—Culex apicalis. Fig. 51.—Mansonia perturbans. Fig. 56.—Culex erraticus. Fig. 52.—Orthopodomyia signifera. Fig. 57.—Me9arbinus septentrionalis. 24 ILLINOIS NATURAL HISTORY SURVEY BULLETIN l'ol. 24, Art. I

along the edge; mesosome with a few flattened and horizontal, fig. 57 ...... short, lateral teeth at apex, fig. 45...... 2. Megarhinus ...... 6. Orthopodomyia Eighth tergite hemicylindrical, shorter than sternite and not at all hoodlike, FEMALE TERMINALIA figs. 49, 52 ...... 6 round and finger-like, wide apart 1. Cerci 6. Cerci with base enlarged, middle con- and directed almost fig. dorsad, 48.... stricted, and apex expanded, fig. 52...... 1. Anopheles ...... 6. Orthopodomyia either closer together, or leaflike and Cerci Cerci with base not at all enlarged, but directed figs. posterad, 49-57 ...... 2 sometimes expanded at apex, fig. 51..7 7. Insula plate well developed as a sclerotized, arcuate, cushion-like crescent, fig. 49; ninth tergite with apical margin rounded and sclerotized, slightly over- hanging base of cerci ...... 3. Uranotaenia Insula plate either entirely membranous or forming a band that bears a small mesal tuft of setae, fig. 53 ...... 8 8. Cerci from edge to edge almost vertical in position, the apex markedly widened ; eighth sternite nearly twice length of eighth tergite, fig. 51 ...... 5. Mansonia Cerci from edge to edge inclining to horizontal in position, the apex narrowed at least slightly, fig. 53; eighth sternite longer than eighth tergite, but not as much longer as in Mansonia 9 9. Postgenital plate parallel sided and truncate, with a long apical seta near each corner and many small setae on the cen- Fig. —Abdomen of adult female, lateral 58. tral area, fig. 161; ninth segment nar- aspect. A, Culiseta inornata; B, Aedes row. A few species of 9. Aedes aegypti; C, Psorophora ciliata. Abbrevia- plate rounded or pointed, with tions: c, postgenital plate. Postgenital cercus ; p, a row or cluster of several scattered F et a e near apex, fig. 54; ninth segment 2. Eighth segment retractile, markedly nar- wide 10 rower than seventh and joined to it by 10. Postgenital plate very wide, as in fig. i6 a wide band of membrane, figs. 58B, C; ...... 8. Culex cerci either long and narrow, fig. 159, or Postgenital plate much narrower, figs. extending far beyond postgenital plate, 53-55 ...... 11 fig. 160 ...... 3 11. A U-shaped internal sclerite present in Eighth segment not retractile, practically membranous folds of spermatheca, fig. the same diameter as the seventh, joined 54 ...... 8. Culex to it by a narrow strip of membrane, fig. No distinct internal sclerite evident in 58A ; cerci short and extending little if folds of spermatheca, fig. 55 ...... 12 plate, at all beyond end of postgenital 12. Ninth tergite forming a sclerotized, fairly figs. 49-57 ...... 4 straight bridge, with a pair of clusters 3. Ninth tergite consisting of a fairly wide, of setae situated close together, fig. 53.. indefinitely outlined rectangular dorsal ...... 7. Culiseta sclerite, figs. 159-167 ...... 9. Aedes Ninth tergit:: consisting of irregular folds Ninth tergite consisting of a heavily scle- at most scmisclerotized, with clusters of rotized, longitudinal rod en larged at setae situated far apart near lateral apex and extending basally beneath margins, fig. 55 ...... 8. Culex eighth tergite, fig. 184..10. Psorophora Postgenital plate extending considerably 1. ANOPHELES Meigen beyond cerci, fig. 50 ...... 4. Wyeomyia Postgenital plate extending only slightly Anopheles is if at all beyond cerci, fig. 49 ...... 5 Of the Illinois mosquitoes, 5. Eighth tergite long and wide, forming a the most distinctive genus and the most flat hood fiat extends considerably be- important one. The larvae, fig. 13, are yond sternite; ninth segment and cerci readily distinguished by the platelike aper-

August, 1947 Ross: MOSQUITOES OF ILLINOIS 25 tore of the breathing apparatus, which in in the hair arrangement of the larvae and in all other Illinois mosquito larvae is tubu- the details of the male genitalia. Conse- lar ; the adults have the scutellum evenly quently, in Illinois the main basis for identi- rounded, not trilobed, and the males have fication of the species in this genus should the apical segments of the palps greatly be the adult females. In other sections of enlarged, fig. 37. According to present the country the larvae may present the only information, Anopheles quadrimaculatus is reliable characters for certain complexes of the chief carrier of malaria in Illinois. the species. Many keys have been presented In proportion to their size, few mosquito for the identification of males by means of the • genera present so many difficulties regard- genitalia. The studies of Roth (1944), ing larval identification as the North Amer- however, have substantiated my own obser- ican Anopheles. There is undoubtedly much vation that the characters of the male geni- variation within many of the species, both talia can be used only on an average basis

Heads of Anopheles Larvae

Fig. 59.—A. barberi. ( After Ross & Rob- Fig. 62.—A. quadrimaculatus. ( After Ross erts.) & Roberts.) Fig. 60.—A. orridentalis (inner clypeal hairs Fig. 63.—A. walker. ( After Ross St Rob- only). erts.) Hair numerals used on this plate are Fig. 61.—A. punctipennis. ( After Ross & those currently employed in the taxonomic Roberts.) literature on mosquitoes.

26 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1 and cannot be used As a means of absolute three abdominal segments with long diagnosis in all cases. feathering, fig. 6+ 2 The recent work of Ross & Roberts 2. Fourth and fifth abdominal tergites with (1943) and Roth (1944) illustrates exten- hairs 0 and 2 plumose, fig. 65 sively many diagnostic and other structural 5. crucians Fourth and fifth abdominal tergites either features of this genus. Additional descrip- with hairs 0 inconspicuous or with hairs tions and a summary of distribution is given 2 only single or double, fig. 64- 3 by King & Bradley (1941), and biological 3. Head hairs 3 very dense, fan shaped from material by Bradley & King (1941). An base, so that no basal stalk is evident, interesting study of variation in larval char- fig. 63; head hairs 2 sometimes feathered acters has been made by Roth (1945b). at tip; prothoracic hairs 1 sometimes To date, five species of this genus have branched 3. walkeri been taken in Illinois. A sixth, occidentalis„ Head hairs 3 less dense, the fan shaped has been taken in Iowa across the Missis- portion beginning some distance from sippi River from Illinois. As it undoubt- base so that a basal stalk is formed, fig. 61; head hairs 2 never feathered at tip; edly occurs in Illinois, it has been included prothoracic hairs 1 rarely branched... in the key. 4 KEY TO SPECIES 4. Second abdominal segment with hairs 1 LARVAE well developed, sclerotized and palmate, 1. Head hairs 5, 6, and 7 short and simple, fig. 64- 2. quadrimaculatus fig. 59; lateral body hairs with only Second abdominal segment with hairs 1 short feathering 1. barberi small, at most fanlike, fig. 65, not at all Head hairs 5, 6, and 7 long and plumose, like the palmate hairs on segment 3 5 fig. 61; lateral hairs of thorax and first

Parts of Anopheles Adults

Fig. 66.—A. punctipennis, wing and mouthparts. Fig. 67.—A. crucians, wing and mouthparts. Fig. 64.—Anopheles quadrimaculatus, larva, Fig. 68.—A. quadrimaculatus, wing and portion of dorsum. mouthpa rts. Fig. 65.—Anopheles crucians, larva, portion Fig. 69.—A q.valkeri, mouthparts. (Figs. 64- of dorsum. 69 after Ross & Roberts.)

August, 7947 Ross: MOSQUITOES OF ILLINOIS 27

5. Head hairs 2 wide apart, fig. 62 Wings without any pale patches, all scales 2. quadrimaculatus dark, fig. 68, except sometimes apical Head hairs 2 close together, fig. 61 6 fringe hairs 3 6. Head hairs 2 always simple, fig. 61 2. Anal vein with 3 short dark bars sepa- 4 punctipennis rated by white bars; palps dark with At least one of the two bead hairs 2 usu- white hands, fig. 67; Costa with a white al]) with a conspicuous branch, fig. 60 spot only at apex of wing...5. crucians occidentalis Anal vein with apical half and extreme base black, and with a single white area ADULTS between; palps black, unhanded, fig. 66; 1. Wings with spots or bars of white or yel- Costa with an apical white spot and lowish-white scales along anterior mar- usually also a preapical spot or bar... gin and anal vein, figs. 66, 67 4 punctipennis

70 BAR BERI

71 B; • QUADRIMACULATUS

Figs. 70--71.—Male genitalia of Anopheles. A, phallosome; B, claspettes; C, ventral aspect of entire structure. Abbreviations: Bs, basistyle; Cl, claspettes; Ds, dististyle; IXT, ninth tergite; Ph-s, parabasal spine; Pk, phallosome; P-IXT, process of ninth tergite; P?, proctiger. ( After Ross & Roberts.) 28 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, "frt. 1

3. Tip of wing with a patch of silvery or bitably from all other North American golden fringe scales; dark wing spots anophelines. very pronounced occidentalis It has been found in only a few of the Tip of wing with fringe not different from many tree holes investigated and is either remainder; dark wing spots frequently much more critical in its choice of breeding obscure 4 place or much less abundant than several 4. Palps narrow and filiform, fig. 38 (fe- other tree hole species such as Lieges tri- males) 5 Palps enlarged into an oval apical club, seriatus. As pointed out by King, Bradley, fig. 37 (males) 7 & McNeel (1939), this species has been 5. Palps black, with white rings, fig. 69.... proved susceptible to malaria parasites but 3. walker; is of doubtful importance in malaria trans- Palps entirely black, without rings, fig. 68 mission. It is widely distributed in the 6 southern and eastern states. 6. Wings without a trace of spotting; wing Illinois Records.—Six larvae, collected June length about 3.5 mm 1. barberi 29 to July 6, and many males and females, col- Wings with definite darker areas giving a lected May 25 to October 10, are from Alton spotted appearance, fig. 68; wing length (usPHs), Cahokia (usPHs), Camp Ellis (usPHs), about 5.0 mm 2. quadrimaculatus Carterville ( USP El ) , Crab Orchard Lake 7. Mesosome without leaflets at apex, fig. 70; (usPHs), Des Plaines, East Alton (usPHs), wing length under 3.5 mm...1. barberi East St. Louis, George Field (usPHs), Hamp- Mesosome with a cluster of leaflets at shire (usPHs), Johnston City (uspns), Marion apex, fig. 71; wing length over 3.5 mm. (usPHs), Momence, Mount Vernon (usPHs), 8 Onarga, Savanna (usPHs), Scott Field (usPHs), 8. Lobes of ninth tergite stout, apex wide, and Springfield (usPHs). sometimes enlarged, fig. 71 2. quadrimaculatus Lobes of ninth tergite narrower, usually 2. Anopheles quadrimaculatus Say tapered at apex 3. walkeri LARVA.—Fig. 62.—Length 8 mm. Head with hairs 2 long, simple and widely sepa- 1. Anopheles barberi Coquillett rated; hairs 3 plumose, branching some distance from base; hairs 5, 6, and 7 long and LARvA.—Fig. 59. Length 6 mm. Head plumose. Thorax and first three segments with almost all hairs simple and unbranched, of abdomen with long feathering on lateral especially conspicuous being hairs 3, 5, 6, major hairs. Abdominal segments 4 and 5 and 7. Thorax and abdomen with only with hairs 2 usually single, rarely double; short feathering on lateral major hairs. of the total of four "hair 2's" on segments Segments 3-7 with a pair of palmate hairs, 3 and 4, seldom is more than one double. segment 2 with moderately developed pal- Palmate hairs on segments 3 to 7, frequently mate hairs. Pecten consisting of an irregu- also on segment 2. Pecten with a series of lar series of long teeth, each tooth with ser- well-spaced long teeth, between each of rations at base. which is a group of three or four short teeth. FEMALE.—Wings with veins having almost Body hairs shown in fig. 64. uniformly dark scales, neither the field of FEMALE.—General color dark brown. the wing nor the fringe with dark spots or Palps entirely dark brown to black, with no light patches. annulations. Wings, fig. 68, uniformly dark MALE.—Similar in color and general scaled, the scaling slightly darker at the structure to female. Genitalia, fig. 70, with fork of R2.3, the base of Rs and the two large parabasal spines; mesosome base of R-1+5. These darker scalings make tapered, without apical leaflets; claspettes four dark spots, sometimes very pronounced, with three setae on the ventral lobe and sometimes scarcely perceptible. three broad scales arising in a compact MALE.—Similar in color and general group from the dorsal lobe. structure to female. Genitalia, fig. 71, with This species contains the smallest individ- two large parabasal spines; mesosome slen- uals of Anopheles in North America, mos- der, its apex with a group of three leaflets quitoes that in general appearance are easily on each side; claspettes each with setae of confused with small dark Culex individuals. dorsal lobe round at tip, those of ventral The setation of the larvae and structures of lobe sharp and pointed. The number of the male genitalia separate this species indu- setae on each lobe varies considerably; if August, 1947 Ross: MOSQUITOES OFILLINOIS 29

only two or three are present on the dorsal Illinois Records.—Many larvae, collected lobe, they may fuse at the tip. June 2 to October 1, and many males and The diagnosis of this species is clear cut females, collected May 16 to November 15, are only in the female. The separation of the from Algonquin, Antioch, Belleville ( uspHs), Benton, Bonnie, Cahokia ( uspHs), Cairo larvae of this species from those of puncti- ( uspHs), Camp Ellis ( uspHs), Camp Grant pennis is frequently difficult. Nearly all ( uspHs), Carbondale, Carterville (uspHs), the specimens I have seen from Illinois will Caseyville, Champaign, Chanute Field ( uspHs), key out without difficulty, but an occasional Charleston, Crab Orchard Lake ( usPHs), Dan- larva is encountered that falls squarely be- ville ( uspHs), Decatur (uspHs), Detroit, tween the two alternatives of couplet 5. in Dubois, Dwight ( uspHs), East Alton ( uspHs), our series of associated larval skins, there East Hannibal, East Moline (usPHs), East is considerable variation in the branching of Peoria (usPits), East St. Louis, Edgemont, hair 2 on abdominal segments 4 and 5; the Edwardsville, Elgin, Elsah, Evansville, French Village ( uspHs), more reliable character seems to be the dis- Galesburg ( uspHs), George Field (usPHs), Gibson City ( usPHs), Gibsonia, tance apart of head hairs 1. The males Glendale, Gorham, Grafton ( uspHs), Grand are extremely close to those of walkeri, Tower, Granite City ( uspHs), Hampshire although in all of our specimens the separa- ( usPHs), Havana, Hecker, Herod, Herrin, tion on the lobes of the ninth tergite is Hull, Johnston City ( usPHs), La Rue, Law- fairly satisfactory. The halteres of quad- renceville ( usPHs), Makanda (usrus), Marion rimaculatus are usually much darker than (usPHs), Milford (usplis), Mississippi Pali- those of walkeri, but these characters vary sades State Park, Momence, Mound City somewhat, and, in preserved specimens, the ( uspHs), Mount Vernon (uspHs), Mulberry difference tends to disappear with time. Grove, Oakwood, Olive Branch, Olney, Omaha, Palos Park, Pere Marquette State In Illinois, the breeding season of quadri- Park, Port Byron, Rockford ( uspHs), Rock maculatus begins nearly a month after that Island ( uspHs), St. Jacob, St. Joseph, Savanna, of punctipennis in the south and of walkeri Scott Field ( usPHs), Seneca ( usPHs), Spring- in the north, indicating a restriction imposed field ( uspHs), Starved Rock State Park, Thom- by water temperature. The preference for son, Urbana, Ursa, Vienna, Waltersburg, and warmer water is further suggested by the Ware. abundance of guadrimaculatus in more open and still bodies of water during the 3. Anopheles walkeri Theobald heat of the summer when punctipennis is found only in more heavily shaded or mark- LARVA.—Fig. 63. In size and general edly cooler waters. The habitat preference color similar to quadrimaculatus. General of quadrimaculatus, which is quite wide, structure of head and body as described for includes small pools, backwaters, and shal- quadrimaculatus, except for the following low basins of large lakes and marshes. differences: head hairs 2 close together, Abundant populations of larvae are almost in our Illinois specimens almost always always associated with emergent vegetation, single and very long, rarely with one or ranging from plants such as Jussiaea diffusa, two fine branches near tip. Abdomen some- which never extends more than a few inches times with well-developed palmate hair on above the water surface, to cattails, rushes, segment 2, segments 4 and 5 with hair 2 and shrubs reaching a height of several feet. usually single and very long, rarely double We have a few records of guadrimaculatus or triple. The best diagnostic character living in running water, but these were in found to date is head hair 3, which is densely situations where the water was shallow branched from the base and therefore lacks and warm, and the flow extremely sluggish. a basal stalk. — Biting records indicate that the females FEMALE. In color similar to guadrimacu- are crepuscular and nocturnal. On cloudy latus with the exception of the palps, fig. 69, days we have noticed a tendency for the which are black with a narrow white annu- females to bite early in the afternoon, but lation at each joint. The wing spotting is normally they bite no earlier than shortly identical with that of guadrimaculatus. — before dusk. Their bites are seldom painful MALE. Genitalia very similar to those and often go unnoticed. of quadrimaculatus, differing in the more This species is considered the most impor- slender lobe of the ninth tergite; usually tant carrier of malaria in the United States the ventral lobe of the claspette has only east of the Rocky Mountains. one stout and one slender seta. 30 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art.1

It is noteworthy that the diagnostic char- tions and by studies in Minnesota and Wis- acters for the larvae of this species, which consin by Daggy, Muegge, & Riley (1941). have been stressed by King & Bradley Illinois Records.—Larvae, taken May 19 to (1941) and by Ross & Roberts (1943), are September 15, and many males and females, not applicable to Illinois specimens. Fol- collected May 19 to November 1, are from lowing are characters listed by these authors Antioch, Beach, Camp Grant (usms), Cary, and, in parentheses, my own observations East Hannibal, Fox Lake, Franklinville, Great on Illinois specimens: head hair 2 finely Lakes Naval Training Station, Lake Bluff, branched at tip (only an occasional Illinois Lake Zurich, Orland Park, Savanna (usmis), Scott Field (usmis), Thomson, Volo, Wau- specimen has these hairs branched and then conda, Waukegan, Woodstock, and Zion. with only one or two branches) ; prothoracic hair 1 branched (this hair is usually single in Illinois specimens) ; and hair 0 dis- 4. Anopheles punctipennis (Say) tinct and many branched (in only a rare Illinois specimen is hair 0 discernible). The LARVA.—Fig. 61. Length 8 mm. Color densely tufted head hair 3, however, is an and general conformation of hairs on head excellent diagnostic character, our associ- and body as for quadrimaculat us. Diag- ated larval skins indicate. This same char- nostic characters as follows: head hairs acter is well illustrated by Ross & Roberts. 2 long and single, the pair close together at This species is abundant in the marshes of base; head hairs 3 each with multiple extreme northeastern Illinois. Outside of branching that begins some distance from this area we have Illinois records from only the base, so that the base of the hair forms three widely separated localities, all from a distinct stalk; palmate hair of second the Mississippi River valley region. These abdominal segment reduced; abdominal seg- three localities are Savanna and nearby ments 4 and 5 with hairs 2 usually double, Thomson (the northwestern corner of the occasionally single or triple, the single, dou- state), East Hannibal (almost at the center ble, or triple hairs occurring in almost any on the western margin), and Scott Field (a combination on different specimens. short distance south of the St. Louis area). FEMALE.—Body dark brown, with the All our collections have been made in cat- mesonotum clothed with grayish scales and tail marshes, to which this species appears the wings definitely patterned with dark to be restricted. In the northeastern cor- and cream color. Palps entirely dark with- ner of the state this species is found in prac- out white annulations. Typical wing pat- tically every marsh and bog in which cat- tern, fig. 66, having a white costal patch near tails are found. The larvae have never apex and a preapical. white patch one-third been found there in abundance. Collecting the distance between apical spot and base which nets one larva per five dips is unusual; of wing, this preapical spot including adja- usually the proportion is closer to one larva cent portions of C, Ri, and 1(2+3 ; in addition per 20 dips. The marshes, however, are there are variable areas of white scales near very extensive in this section, and the species the base of Rs and M, Mi, and 1142; a is quite abundant. Unlike the females of diagnostic and stable area of white scales quadrimaculatus, the walkeri females bite occupies most of the basal half of the anal readily during the day as well as during the vein. evening. In early summer they are espe- MALE.—General structure and color, cially vicious and will attack a person in especially wing pattern, as for female. Gen- bright sunlight. italia in general as for quadrimaculat us In northeastern Illinois, adults and full with the following average differences in grown larvae have been collected early in the claspette: dorsal lobe usually with only June and also late in October. The species one seta, which may be round or pointed at has a great tolerance for cool water and is apex; ventral lobe usually with only one similar to zl. punctipennis and C uliseta inor- stout and one narrow seta in addition to one nata in this respect. or two short setae. It is interesting to note that walkeri is Occasional larvae are found that seem to considered rare south of northern Illinois. bridge the gap between punctipennis and In northern Illinois and northward, it is one quadrimaculatus. The number of such of the dominant species of the anopheline larvae, however, appears so small as to be populations, as shown by our Illinois collec- of no statistical importance in proportional ilugust, 1947 Ross: MOSQUITOES OFILLINOIS 31

counts because 99 per cent of all the larvae dence at present indicates that punctipennis taken can be identified with certainty. is not an important carrier of malaria under Extreme variation of wing pattern has natural conditions, although the species be- been found in Illinois material of this comes infected readily under experimental species. Two wing spots appear to be con- conditions. stant, the apical costal spot and the white Illinois Records.—Many larvae, collected bar on the base of the anal vein. All the May 14 to October 14, and many males and other spots vary greatly, and occasionally females, collected April 17 to November 29, additional white bars appear on practically are from Albion, Algonquin, Belleville all the radial and medial veins. The pre- (usPHs), Brubaker, Cache, Cahokia (usPHs), apical spot is subject to the most conspicuous Cairo, Calvin, Camp Ellis ( usPHs), Camp Grant (usPHs), variation. Usually it is about one-half as Carbondale, Carterville (usmis), Champaign, Chanute Field (usPHs), long as the dark bar separating it from the Charleston, Council Hill, Crab Orchard Lake apical spot. In the light extremes, the pre- ( usPHs), Decatur ( usPHs), Dixon Springs, apical spot may be fully as long as this dark Dwight ( usPHs), East Alton (usPHs), East bar ; in dark extremes the preapical spot may Moline ( usPHs), East Peoria ( usPHs), East be only a quarter or a sixth as long as the St. Louis, Edwardsville, Effingham, Elsah, bar ; and in rare instances no preapical spot Epworth, Florence, Forest Glen, Fox Lake, may be present. Our collections indicate Fox Ridge State Park, French Village ( usPHs), that there is no particular significance to Fulton ( usPHs), Galesburg (usPHs), George these variations. We have taken a wide Field ( usPHs), Giant City State Park, Gibson City ( usPHs), Gorham, Gossett, Grafton range of these types in a single collection ( usPHs), Grand Tower, Granite City (usens), from one locality, and seldom does a large Grantsburg, Greenville, Grimsby, Hamilton, collection from one locality present even a IIavana, Herod, Herrin, Joetta, Johnston City reasonable homogeneity in regard to wing ( usPHs), Jonesboro, Kankakee, Karnak, Keiths- spots. burg, Laclede, La Grange, Lake Villa, La Rue, In Illinois, punctipennis is undoubtedly Lawrenceville (uspHs), Lima, Maroa, Marion the most widespread and common species ( usPHs), McClure, Michael, Mill Shoals, Mis- of zlnopheies. It breeds in a wider variety sissippi Palisades State Park, Momence, Mount of aquatic situations than the other species Carmel, Mount Vernon ( usPHs), Mulberry in the genus. We have taken it in running Grove, Muncie, Neoga, New Athens, New Haven, Nutwood, Oakwood, Oak Park, Olney, streams, backwaters of lakes, cattail marshes, Omaha, Palos Park, Pere Marquette State densely wooded cypress swamps, and open Park, Pingree Grove, Pittsburg, Pittsfield, and practically barren pools. In southern Quincy, Richmond, Ridge Lake, Rising Sun, Illinois, it is the earliest anopheline to make Rockford (usPHs), Rock Island ( usPHs), Rock- its appearance, the first adults usually ton, St. Jacob, St. Joseph, Salem, Savanna emerging by about the middle of April. In ( usPHs), Scott Field (usPHs), Seneca ( usruis), the northern part of the state, mature larvae Springfield, Starved Rock State Park, Sugar and pupae have been collected in the mid- Grove, Thomson, Urbana, Ursa, Utica, Viola, Waltersburg, Ware, Waterloo, Wauconda, dle of October. In early spring it shows a White Heath, White Pines Forest State Park, preference for open sunlit water. In the Willow Springs, Wolf Lake, and Zion. heat of summer, at least in southern Illinois, it leaves the open situations almost entirely and breeds in fairly densely shaded situa- 5. Anopheles crucians Wiedemann tions, such as pools and creek beds, running streams, cypress swamps, or woodland pools. LARVA—Fig. 65. Color, size, and general Both seasonal distribution and habitat indi- conformation of hairs on head and body as cate a preference for cooler water than that for quadrimaculatus. Diagnostic characters frequented by quadritnaculatus. In the as follows: head hairs 2 long and single, the northern part of the state this segregation pair close together at base; head hairs 3 each is not so pronounced; here punctipennis and with multiple branching that begins some quadrimaculatus are frequently taken to- distance from base, so that the base of the gether in the same body of water. hair forms a distinct stalk; palmate hair of Although punctipennis is extremely widely second abdominal segment reduced; abdom- distributed, it has never been found in the inal segments 4 and 5 with hairs 0 and 2 tremendous local abundance that character- multiple and conspicuous. izes populations of quadrimuculatus. Evi- FEMALE.—Body dark brown, the niesono- 32 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, lrt. 1

turn clothed with linear areas of grayish larvae. According to previous workers, the scales, and the wings patterned with dark eggs are laid singly on the surface of the and cream color. Palps dark, with the short water. apical segment white and with a conspicu- Only a single species, septentrionalis, has ous white band at the base of the third seg- been taken in Illinois. The only other ment. Typical wing pattern, fig. 67, having Nearctic species, rutilus Coquillett, is very the costal margin entirely dark scaled except closely allied and has never been collected for a white patch at the apex of the wing; in north of the extreme southeastern United addition there are areas of white scales on States. all the veins posterior to R,.; a diagnostic feature is the alternation of white and dark- 1. Megarhinus septentrionalis scaled areas on the anal vein. Dyar & Knab MALE.—General structure and color, especially wing pattern, as for female. Geni- LARVA.—Fig. 19. Head quadrate, with talia very similar to those of punctipennis well-developed mouth brushes; antennae males. very short, with only one or two minute In Illinois this species has been taken in setae; dorsum of head with only a few minor numbers only in the St. Louis area and setae. Body hairs long and stout, each seg- southward. Two apparent stragglers have ment of thorax with one sclerotized plate been taken north of this area, one at Havana bearing the dorsal lateral tuft and another and one at Peoria. The species is wide- bearing the ventral lateral tuft. Segments spread south of Illinois, and our records 1-7 of the abdomen with the long seta situ- represent probably the northern edge of its ated on tubercle-like sclerotized plates, the range. first segment with four on each side, the Our only larval records are from cattail remaining segments with three, each bearing marshes in the IVIississippi River valley. In one to several long setae. Eighth abdominal an extensive cattail marsh at La Rue, Illi- segment with a large lateral sclerite bearing nois, this species was especially abundant. several long apical setae and representing The larvae were taken in company with the lateral comb. Air tube short and stout, those of quadrimaculatus, which outnum- with a pair of ventral tufts near base. Anal bered the crucians larvae almost two to one. segment large, completely enclosed in a Light trap collections indicate that crucians heavily sclerotized ring, and having short is never a dominant feature of the mosquito budlike gills and hair tufts as in fig. 19. fauna in Illinois. FEMALE.—Length of wing 7 mm. Body Illinois Records.—Many larvae, collected and appendages with metallic iridescent May 22 to October 1, and many males and scales. Palps and beak a mixture of bluish- females, collec:ed June 16 to October 4, are purple and gold scales, dorsum of head from Alton (usms), Cache, Cahokia (usPHs), greenish. Mesonotum with lateral and Carterville (usPHs), Crab Orchard Lake, East Alton (usPHs), East St. Louis, Granite City mesal stripes of greenish gold, the interven- (usPHs), Ilavana, Herrin, Johnston City ing bands black, purple, and green. Dor- (usPHs), La Rue, Marion (usPHs), Mount sum of abdomen almost entirely greenish Vernon (usPHs), Peoria (usPHs), and Scott purple, apical segments with a few lateral Field (usPHs). patches of silvery scales; venter almost entirely creamy gold, with a mesal greenish- 2. MEGARHINUS Robineau-Desvoidy purple stripe. Legs, for the most part, purplish; the middle and hind tarsi with the Individuals of this genus are among the second, third, and fourth segments white; most peculiar in the state. The adults are the hind tarsi with the fourth and fifth seg- large and brilliantly colored. The probos- ments white; the femora with the base and cis is markedly curved, as in figs. 33 and 34, posterior face of each mostly cream. Wings not adapted for biting but for feeding on entirely purple scaled. The female geni- nectar. The larvae as well as the adults talia are dorso-ventrally compressed, fig. 57, are very large and may be identified immedi- and in this respect the species is quite unlike ately by the small sclerotized plates upon any other Illinois mosquito group. which many body setae are situated. The MALE.—In size and general color similar larvae are restricted to tree holes, in which to female. The tarsi are black, except for they are predaceous upon other mosquito the fourth segment of the hind tarsi, which August, 1947 Ross : MOSQUITOES OF ILLINOIS 33

and a narrow mesal line down the is clothed with dirty white scales. The prono- turn, palps are very long and black, fig. 33. Male from near the anterior margin to the tip of the scutellum, bright iridescent blue. genitalia, fig. 47, fairly simple in general Abdomen dark brown with irt egular apical structure, resembling in many respects those patches of dirty white scales at the apex of Culiseta; differing most markedly in of some segments. Legs dark brown, each the shape of the dististyle and ninth tergite. with a small conspicuous knee patch and a We have only a few scattered records of small patch on upper side of tip of tibia, this species, all from the southern third of each patch consisting of a cluster of white the state. Our records from Carbondale scales. Wings brown scaled, except for a are based on captures of free-flying adults; line of blue scales covering the stem of specimens from Scott Field and Edwards- Cubitus. All the brown scales of the wings ville were collected as immature stages in and legs are iridescent, appearing greenish tree holes in oak-hickory woods. The spe- blue in certain lights. cies has been reported as widespread MALE.—Similar in size and general struc- throughout the southeastern states. ture to female; in this sex also the palps are Illinois Records.—CARBONDALE : Aug. 7, 1927, 1 ? ; 1941, 2 2 ; EDWARDSVILLE : Sept. 24, 1943, small and budlike, fig. 32. Genitalia, fig. from tree hole, 1 ; SCOTT FIELD: Aug. 13, 44, with basistyle short and robust and with 1942, tree hole, 2 larvae; Aug. 24, 1942, fallen- a cluster of five or six longer spines on the tree hole, 1 8 ; Sept. 16, 1942, tree hole, 1 mesal face; dististyle short, the apex nar- larva. rowed and hooked, without conspicuous apical seta. Ninth tergite developed into a 3. URANOTAENIA Arribalzaga very large bibbed plate that extends over the tenth segment and mesosome. Individuals in this genus are small. Both The larvae of this species, which is wide- adults and larvae present a number of dis- spread in Illinois, live in permanent or semi- tinctive characters that set them off readily permanent ponds, preferring weed-choked from other mosquitoes in Illinois. Of the situations. In northern Illinois they occur three species of Uranotarnia known to occur in several cattail marshes and in southern in North America, only one has been taken Illinois are usually associated with dense in Illinois. marginal growths of Jussiaea, especially

1. Uranotaenia sapphirina ( Osten Sackett)

LARVA.-Fig, 72. Length 5 mm. Head elongate, the upper and lower head hairs represented by long stout spines. Antennae short with a few sharp spines at apex. Thorax and first two segments of abdomen with long stout lateral hairs, abdominal segments 3-7 with only fine tufts of hairs. Lateral comb of eighth segment represented by a large sclerotized plate bearing a row of 8 to 10 teeth on its apical margin. Air tube elongate and slender, the pecten distinct and containing about 15 spines, the ventral tuft large and situated at the end of the pecten. Anal segment longer than deep, completely encircled by the sclerotized ring, the anal gills finger-like, slender, but only about as long as the anal segment. FEMALE.—Length of wing 2.5 mm. Palps minute and budlike. Head and thorax, including beak, dark-brown scaled; dorsum of head, antero-lateral lobe of pronotum, Fig. 72.—Uranotaenia sapthirina, larva. A, patches of scales on the pleurae, a narrow apex of abdomen, lateral aspect; B, dorsum line on the extreme edge of the mesonotum, of head. 34 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Lim'. .1

where this plant occurs in combination with row. Air tube small, slender, with about cattails or other marsh plants. They are 15 pairs of long single hairs scattered along very much like anopheline larvae in peculi- its length. Anal segment almost ringed by arities of movement when diving or coming the sclerotized plate. The apex of this to the surface. The species appears fairly plate bears dorsally two pairs of long dou- late in the season, apparently in response to ble hairs and a single pair of lateral double the warmer waters of the summer season. hairs; at the postero-ventral corner of the The adults apparently do not bite. Pre- plate is a pair of double or triple hairs. No sumably they feed on nectar. The females ventral brush is present. The anal gills, lay eggs in irregular rafts on the surf ace of two in number, are large and sausage shaped ; the water. a second pair of gills may be represented by This species has a wide range that em- a pair of small swellings above the base of braces most of the United States east of the the conspicuous gills. Great Plains and has at least scattered rec- FEMALE.—Length of wing 3 mm. Beak, ords from Minnesota to the extreme south- dorsum of head, mesonotum, .and dorsum ern states. It has been reported from south- of abdomen almost uniformly covered with ern Illinois by both Chandler (1920) and a mat of iridescent bluish-black scales. Matheson (1930) and from various local- Pleurae and venter uniformly covered with ities in the Chicago area by Gerhard (1910). creamy or silver scales. Scales of mesono- Illinois Records.—Larvae, collected June 3 turn forming a dense appressed mat with- to August 27 and many males and out setae projecting above it, but with setae females, collected May 23 to October 21, are projecting from beneath it at the sides and from Cahokia ( usPHs), Cairo ( usPHs), Camp along the posterior margin. Postnotum with Grant (volts), Carterville ( uscits), Chanute a small cluster of minute setae. Legs, for Field ( usPHs), Charleston, Crab Orchard Lake the most part, blue black, whitish blue be- ( vsPtis), East Hannibal, East St. Louis, Edwardsville, Effingham, Elgin, Elsah, Fox neath, iridescent; the middle pair may have Lake, Fox Ridge State Park, Gibsonia, Gossett, the apical two or three segments predomi- Grafton ( usPHs), Granite City ( vsPits), Great nately white scaled, at least on the outer Lakes Naval Training Station, Havana, face. Wings uniformly deep bluish-brown Hecker, Herod, Herrin, Homer, Johnston City scaled. ( vsPHs), Lake Glendale, La Rue, Marion MALE.—Similar in size, color, and struc- (volts), Mount Carmel, Mount Vernon ture to female. The palps are short and Muncie, Oakwood, Omaha, Ottawa, ( ustHis), abortive as in female. The male genitalia, Peoria ("isms), Putnam, Raymond, S akin, fig. 46, have a long slender basistyle and are Savanna, ( vsPHs), Scott Field ( usPHs), Seneca ( usPHs), Springfield ( vsPits), Starved Rock distinguished from those of all other Illi- State Park, Sugar Grove, Thomson, Urbana, nois mosquitoes by the curious processes of Volo, Wauconda, and White Pines Forest the dististyle. State Park. In Illinois this little mosquito is found only in the tamarack bogs of the northeast- 4. WYEOMYIA. Theobald ern corner of the state. The larvae live in the water contained in the pitchers of the This genus is represented in Illinois by pitcher plant, Sarracenia purpurea Linnaeus. only the pitcher plant mosquito, smithii. The species overwinters as larvae in the The males are readily identified by the pitcher plants, and the adults emerge the curious shape of the dististyle, fig. 46. The following summer. The females, which lay larvae, fig. 20, have very distinctive charac- eggs in the pitchers, apparently do not bite. ters in the structures of the terminal seg- The adults are quite active during the day, ments. flying around the pitcher plants. They are very difficult to follow in flight; they have 1. W yeomyia smithii ( Coquillett) an irregular and slow flight pattern that LARVA.—Fig. 20. Length 6 mm. Head combines with the gangling legs and irides- longer than wide, somewhat ovate, antennae cent color to make it difficult for an observer short, without conspicuous lateral tufts. to be sure just how far away they are. The Dorsum of head with only a few indistinct development of the larvae is apparently hairs. Body hairs very long. Eighth seg- very slow. In this respect the pitcher plant ment with a lateral comb consisting of mosquito resembles the tree hole species. about eight scales arranged in a straight The range of the species includes most of Jugust, 1947 Ross: MOSQUITOES OF ILLINOIS 35 the northeastern states, wherever the segment, the latter predominating at the pitcher plant occurs. Two other species in apex. Femora and tibiae with an irregular the genus occur in southern Florida. A key mixture of brown and pale scales, the poste- to the females is given by Roth (1946). rior face of femora chiefly cream scaled; Illinois Records.—CEDAR LAKE: in bog, Aug. tarsal segments 2-5 each having the basal 3--6, 1906, Shobe, 3 9 ; Aug. 6, 1906, 1 S ; Aug. half white scaled, the apex black scaled; 7, 1906, 7S, 229. MCHENRY: Nov. 10, 1927, basitarsi with a narrow basal band of white in pitcher plant, H. H. Ross, 3 larvae. Vow: scales and an irregular central band of white in pitcher plant, July 1, 1942, Ross & Mohr, scales. Wings with an indiscriminate mix- 3 larvae; July 3, 1942, Ross & Mohr, 15 larvae ; ture of white and brown scales, the scales July 8, 1942, Ross & Mohr, 9, 2 pupal skins; 2 all broad. July 19, 194-2, Ross & Mohr, 12 S, 1 ; Oct. 27, 1943, Ross & Sanderson, 1 S MALE.—In size, color, and general structure similar to female. Palps longer than beak, the apex of the second segment and the 5. MANSONIA Blanchard entire third and fourth segments with a Modifications in the larva make this ventral brush. Genitalia, fig. 43, with ninth genus of unique interest. The larval air tergite strap shaped and having a pair of tube forms a sharp piercing structure that conspicuous ventral lobes. Basistyle fairly is inserted into the roots or underwater stout, its mesal face with few setae and with stems of vascular plants; it pierces the air a single long stout beaklike spine. Disti- chambers of these, and the larva draws on style twisted and angulate at base, narrow, the air in these chambers for its respiration. expanded, and bladelike at apex, its apical Thus, the larva does not need to come to spine forming a stout sharp tip. Lobes of the surface for air. Otherwise the larva tenth sternite moderately long and evenly and the adult are very similar to those of toothed. Mesosome short and stout, with allied mosquitoes. The eggs are laid as a row of stout but minute dorsal teeth. rafts on the surface of the water. A single species, perturbans, occurs in Illinois. The only other United States species are the tropical titillans ( Walker) and indubitans Dyar & Shannon, which are found in southern Florida (Pratt 1945). The species perturbans is placed in the subgenus Coquil- lettidia Dyar.

1. Mansonia perturbans ( Walker)

LARVA.—Fig. 73. Head wider than long, antennae slender and long, with a fan- shaped tuft near middle; dorsum of head with many multiple tufts. Thorax and abdomen with many long setae. Eighth segment with an irregular row of scales forming the comb. Air tube, fig. 18, with a wide base, the apical sclerites long and sharp, forming a stout piercing organ. Anal segment fairly narrow, completely encircled by a sclerotized ring; anal gills pointed, shorter than segment. FEMALE.—Length of wing 4.5 mm. Beak with a mixture of brown and pale scales, the latter forming an indistinct central ring. Dorsum of head and mesonotum with brown scales and hair, the mesonotal setae abundant, long and recurved. Abdomen with a mixture of pale and brownish-blue scales, Fig. 73.—Mansonia perturbans, larva. (After the former predominating at the base of the Matheson.) 36 ILLINOIS NATURAL HISTORY SURVEY BULLETIN VOL 24, Art. 1

Taken in only a few areas of the state, species are practically identical in chaeto- this species is most commonly encountered taxy and formation of the lateral comb. in the marshes of the extreme northeastern It has been suggested that the color of corner and south to the Chicago area. A the base of the abdomen would separate few other records have been taken extend- these two forms in the adult stage. Isolated ing to the southern third of the state. Adult rearings have demonstrated that this differ- records occur from June through August. ence does not hold, at least for Illinois speci- Males have been taken only in the early mens. It is therefore impossible at present part of this period and suggest that there to give a key for the specific diagnosis of is only a single generation per year in Illi- males or females. nois. The species is associated chiefly with cattails and aquatic sedges. In the southern KEY TO LARVAE states, pickerelweed, arrowhead, and other Head medium to dark brown, body pink; plants are frequently preferred for larval segments 6, 7, and 8 usually with dorsal attachment. sclerotized plates, the plate of segment The females are voracious biters, espe- 8 frequently extending ventrad to the cially in the cloudy afternoons and the cre- ventral margin of the comb, fig. 17; these sclerotized plates may be entirely puscular periods. absent 1. signifera Gerhard (1910) recorded this species as Head capsule very pale yellow to white, common and annoying in tracts of woodland body white to straw color; segments 6, in the Chicago region and encountered rarely 7, and 8 without sclerotized plates.... on the south side of the city. Specimens 2. alha from Roxana, Danville, and also Algonquin were recorded by Matheson (1930). J. LyeII I. Orthopodomyia signifera (Coquillett) Clarke has told me of occasional swarms of this species which were very annoying to LARVA.—Fig. 17. Length 7 mm. Head the workers in several industrial plants on dark brown, somewhat oval, slightly longer the south side of Chicago. than wide; upper and lower head hairs The species is widely distributed through- multiple and fan shaped, the lower hairs out the eastern United States, from Minne- close to the uppers and more laterad than sota to Florida. anteriad; between them is a pair of shorter Illinois Records.—Adults, collected May 21 fanlike tufts. Thorax and abdomen with to September 19, are from Algonquin, Beach, many long hairs. Seventh abdominal seg- Belleville (usPiis), Cahokia (ustros), Camp ment frequently with a large dorsal sclero- Grant (usms), Carterville (usmts), Danville, tized shield, which may be reduced to a pair East St. Louis, Elsah, Grand Tower, Granite of small dorsal sclerites or even be entirely City (usmts), Great Lakes Naval Training Station, Herrin, Johnston City (usrns), Marion absent. Eighth segment usually with a large (usPus), Oak Park, Peoria (uses), Pere Mar- dorsal sclerotized shield; this may be so quette State Park, Roxana, Savanna, Starved large that it extends to the ventral end of Rock State Park, Volo, and Zion. the lateral comb but it may be much smaller or in rare individuals practically absent. 6. ORTHOPODOMYIA Theobald Lateral comb consisting of two distinct series of scales, an anterior row of 15 to 20 The Illinois species of this genus are char- small scales and a posterior row of about 5 acterized by the curious mesonotal pattern very large long scales. Air tube about three of the adults, fig. 27, and by the air tube, times as long as wide, having no pecten but basal sclerite, and anal segment of the larva, having a large ventral tuft just before mid- fig. 17. Two species are known from Illi- dle. Anal segment with a basal barlike nois, both of which occur only in tree holes. sclerite, the main portion of the segment The status of these two species is very puz- completely surrounded by the sclerotized zling. To date no distinguishing characters ring and with pointed gills, the upper pair have been discovered either in coloration of much longer than the segment, the lower the external areas or in the structure of the pair about as long as the segment. male genitalia. The larvae, however, differ FEMALE.—Length of wing 4 mm. Entire quite markedly both in color and in the body principally dark brown to black scaled, average sclerotization of the seventh and dull and velvety. Beak and palps with irreg- eighth abdominal segments. Larvae of both ular rows of white scales, dorsum of head August, 1947 Ross: MOSQUITOES OF ILLINOIS 37

with scattered white scales and a prominent To date, all but one of the larval colonies row around posterior margin of eyes. IVIeso- of this genus that we have encountered in notum with narrow but sharp lines of white Illinois have been those of signifera. For scales, fig. 27. First abdominal tergite and this reason we have tentatively considered base of second usually white scaled. Femora all field-collected adults of Orthopodornyia with a scattering of white scales, tibiae with to be of this species. irregular lines of white scales. Tarsi black, This species was reported from the Chi- the anterior pair with a minute white patch cago area by Gerhard (1910) as Baneroftia at end of basitarsus, the middle pair with signif era and from Urbana by Matheson patches of white at base of apex. Basitar- (1930). sus and the hind pair with basal apical Illinois Records.—Larvae, collected June 29 patches on the first four tarsal segments to July 3, and adults, collected June 5 to Sep- and on the dorsum of the last segment. tember 30, are from Cahokia (usPH.$), Des The white bands on only the first two tar- Plaines, East St. Louis, Galesburg, Glencoe, sal segments of the hind legs are wide Havana, Mahomet, Onarga, Ridge Lake, Scott Field (usPits), Thebes, and Urbana. enough to form conspicuous bands. Wings with a conspicuous mottling of white scales that form definite patches on the base of the 2. Orthopodomyia alba Baker anal vein and around the point where R2.3 Similar to signif era in adult characters and Rm, divide from each other. and in general characteristics of the larva; MALE.—Size, color, and general struc- differing as outlined in the key. Only a ture essentially as for female. Palps elon- single colony of this species has been encoun- gate, as long as beak, black scaled, without tered in Illinois. It was found in a tree hole tufts, but apical segment with 15 or 20 fairly —in a soft maple tree at Onarga, where it long stiff setae projecting irregularly on all occurred with signif era. This dual colony sides. Male genitalia as in fig. 45. Ninth has persisted for several years, the alba tergite mostly membranous, without definite larvae slightly more abundant than the sig- ventral lobes. Tenth sternite of medium nit era larvae. Individual rearings from length, ending in a series of three or four this colony established the similarity in color closely appressed teeth. Mesosome about of the adults of the two forms. as long as tenth sternite, with short lateral teeth near apex. Basistyle elongate, with a ventral mesal cluster of stout setae; at its 7. CULISETA Felt base is a mesal arcuate lobe that bears an Only two species of this genus have been even cluster of stout setae. Dististyle slen- taken in the state. A third species, tnelanura der and elongate, tipped with a short stout ( Coquillett), is widespread to the east and seta that is truncate at apex, the end appar- south. The few remaining species of the ently with a cone-shaped hollow. genus are northern or western in distribu- Widely distributed over Illinois, this spe- tion. The eggs are laid in rafts on the sur- cies breeds exclusively in tree holes. The face of the water. The adults resemble large eggs are laid singly at the water's edge and specimens of Culex, but the larvae are read- hatch in a few days. As seems true with all ily distinguished from other mosquito larvae the tree hole mosquitoes occurring in this by the large basal tuft on the air tube. latitude, the larvae apparently grow rather slowly. Emergence of adults begins toward KEY TO SPECIES the end of June and continues through the LARVAE summer. Apparently females of the species Tube short and stout, fig. 74- 1. inornata bite humans only on rare occasions and are Tube longer and slender, fig. 75 . .2. morsitans not a pest. Superficially the adult resem- FEMALES bles the yellow-fever mosquito, A edes Tarsi without pale rings on the segments.... aegypti. The adults can usually be found 1. inornata most readily sitting in and around tree cavi- Tarsi with faint whitish rings at both ends ties. of the segments 2. morsitans The species is widely distributed through- MALES out many of the eastern states, although it Mesosome consisting of a pair of long, slender does not occur much farther north than black rods tipped with a small membranous Illinois. piece, fig. 78 1. inornata 38 ha.J.Nois NATURAL HISTORY SURVEY BULLETIN V ol. 24, Art. 1

Mesosome wide, bulbous in central portion as long as wide; pecten long, the basal 10 and only lightly sclerotized, fig. 77 to 12 scales sclerotized and dark, the re- 2. morsitans mainder longer, hairlike, and almost color- less; ventral tuft composed of about eight 1. Culiseta inornata ( Williston) long stout hairs situated near the base of the air tube on the ventral aspect mesad of LARVA.—Fig. 74. Length 10 mm. Head the pecten. Anal segment completely en- capsule wider than long, upper and lower circled by sclerotized ring; anal gills long head hairs fan shaped, the lower ones usu- and tapering, longer than segment. ally quadruple, the upper ones with about FEMALE.—Wing length 6 mm. Beak, eight rays; in front of the upper hairs is an head, mesonotum, and most of legs a mix- accessory pair of tufts, each with about four ture of brown and gray scales; pleurae, ven- hairs. Hairs of thorax and abdomen of only ter of abdomen, and ventral face of most medium length. Eighth segment with a tri- of legs with gray or cream-colored scales angular comb consisting of about 50 scales. predominating. Dorsum of abdomen with Air tube fairly long, a little over three times basal bands of cream and tawny scales, apical

Larvae of Culiseta Fig. 74.—C. inornata: A, dorsum of head ; Fig. 75.—C. morsitans: Ii, dorsum of head ; B, apex of abdomen. B, apex of abdomen. Jugust, 1947 Ross: MOSQUITOES OF ILLINOIS 39 portion brown scaled. Wings mostly brown composed of two long sclerotized plates with scaled but with a mixture of tawny scales a slender membranous tip. along most of the anterior veins. In some One of the common marsh mosquitoes in specimens Costa and Radius almost entirely Illinois, this species is most abundant in the tawny scaled; in these the legs may be pre- northeastern quarter of the state, where it dominantly tawny scaled throughout. is found in numbers in almost every marsh. MALE.—Form slender compared to that Farther south it occurs in marshes, sink of female. Pattern in general similar to holes, stump holes, and artificial ponds. In Illinois the species apparently has an early spring and late summer generation with a fairly definite period of inactivity during the hottest period of the summer. The two- brooded condition is especially pronounced in southern Illinois, where the first wave of 76C adults comes out in April and early May IMPATIENS 77C MORSITANS and the next in September and October. The eggs are laid as rafts on the surface of the water. The adults apparently overwinter and are frequently encountered entering houses, presumably to hibernate, during warm days of November and December. In early spring the overwintered females bite ferociously, but during the summer this species does not seem to constitute much of a pest even in those regions where it is abundant. Very common throughout almost the entire United States, the species is essentially a winter form in the extreme southeast, according to King, Bradley, & McNeel (1939) ; in higher elevations of the Rocky Mountains it is primarily a midsummer form. Illinois presents an interesting intermediate between these two extremes. The species was recorded from the vicinity of Chicago under the name Culiseta consobrinus ( Robineau-Desvoidy) by Gerhard Figs. 76-78.—Male genitalia of Culiseta. (1910). Matheson (1930), who recorded /./, genital capsule, ventral aspect; B, meso- it as common and widespread in Illinois, some, dorsal aspect; C, lobe of tenth sternite, listed several localities. In the same paper lateral aspect. he listed a male from Carbondale, Illinois, as Theobaldia impatiens (Walker) ; the that of female but with the cream and tawny cleared genitalia of this specimen show that scales replaced almost entirely by lemon it is a typical specimen of Culiseta inornata. scales, with little or no banding on the dor- Illinois Records.—Larvae, collected April 6 sum of the abdomen but with the eighth to October 22, and adults, collected March 16 tergite almost entirely yellow scaled. Palps to November 16, are from Algonquin, Alton, longer than beak, slender, and without con- Amboy, Antioch, Cache, Cahokia (usPHs), spicuous brushes, both palps and beak largely Cairo (uspHs), Camp Grant (usPHs), Carbon- yellow scaled, except at tip. Genitalia, fig. dale, Carterville (usPHs), Cottage Grove, Crab 78, with basistyle fairly long, robust, and Orchard Lake (usPHs), Dupo, Durand, East Moline (usPHs), East Peoria (usPHs), East tapering, with a small meso-basal area bear- St. Louis, Effingham, Eldorado, Elk Grove, ing a dense patch of setae. Dististyle slen- Elsah, Farmer City, George Field (usPH8), der, tipped with a pair of short stout tooth- Gilman, Glencoe, Grand Tower, Granite City like setae. Lobes of tenth sternite ending (usPHs), Grantsburg, Great Lakes Naval in a few sharp teeth, much fewer than in Training Station, Harrisburg, Havana, Hazel- impatiens ( Walker), fig. 76. Mesosome crest, Herod, Herrin, Highland, Hinsdale, Kan- 40 ILLINOIS NATURAL HISTORY SURVEY BULLETIN ol. 24, Art. 1 kakee, Karnak, Keithsburg, Makanda, Marion specimens. The next year the bog was vis- (uspns), McLean, Mazon, Mill Shoals, Mis- ited on April 19, and scattered specimens sissippi Palisades State Park, Momence, of the larva were found in the cool, shaded Mount Vernon, Mount Zion, Muncie, Neoga, pools around the base of the old tamarack New Boston, Orland Park, Palatine, Palos hummocks. Efforts to rear some of these Park, Pere Marquette State Park, Ravinia, Rockton, Roxana, St. Jacob, Savanna (usPns), specimens were not successful. The speci- Scott Field (usPns), Seneca (usPris), Spring- mens were transported to Urbana, where field (usPHs), Starved Rock State Park, Urbana, at the time fairly high temperatures pre- Wadsworth, Waltersburg, Ware, Waukegan, vailed, and all the larvae died. It is interest- White Heath, Willow Springs, Wolf Lake, ing to note that larvae of several species of Woodstock, and Zion. dedes, brought back at the same time and given the same treatment, emerged without 2. Culiseta morsitans (Theobald) difficulty. On a subsequent visit to the bog on May 19, 1944, larvae were found in the LARVA.—Fig. 75. Length 9 mm. Head same place and apparently completely full very wide, almost rectangular. Upper head grown. On this occasion, jars in which hairs usually four or five branched, lower larvae were placed were wrapped in moist head hairs double and extremely long; be- cloths for the trip to Urbana and after- tween them is a pair of extremely minute wards were kept in a water bath at a tem- hairs. Antennae long and curved with a perature of about 60 degrees F. These large tuft near apex. Thorax and abdo- larvae matured and transformed slowly but men with many very long hairs. Eighth successfully. segment with large triangular lateral comb Although no other records for Illinois consisting of about a hundred minute scales. have been taken, we have in the collection a Air tube extremely long and slender, nearly female from Lake Delavan, Wisconsin, and seven times as long as wide; pecten consist- two females from Minocqua, Wisconsin, ing of only a few flat teeth on basal fourth; which are of this same species; these were ventral tuft on ventral margin at extreme incorrectly recorded as impatiens ( Walker) base. Anal segment entirely enclosed by by Matheson (1930). sclerotized ring, with hairs of ventral brush arising through ring; anal gills slender and 8. CULEX Linnaeus pointed, about as long as segment. FEMALE.—Length of wing 5 mm. Color The eight species of this genus that occur dark bluish brown, the dorsum of head in Illinois have a continual series of gener- mostly gray scaled, mesonotum with a few ations throughout the warmer months of the small spots and lines of gray scales. Dorsum year. The females lay their eggs in rafts of abdomen with a basal gray band on each on the surface of the water. The species segment, the apical portion of the segments frequent still or semistagnant water of all brown scaled. Legs almost entirely bluish- types and may be found even in lakes of some brown scaled with faint but distinct narrow size, the larvae breeding in masses of float- rings at the base of most of the tarsal seg- ing or emergent vegetation. Usually the ments. Wings entirely blue-brown scaled. larvae are taken in association with anoph- MALE.—Similar in size and color to eline larvae. female. Palps elongate, differing markedly The genus as a whole is tropical or sub- from those of inornata in having long ven- tropical in distribution. Many North Amer- tral brushes at the apex of the second and ican species occur in the southeastern states, on all of the third and fourth segments. southwest Texas, and southern California. Genitalia similar in general outline to those In the Neotropical region, the genus is rep- of inornata, differing markedly in the shape resented by a very large number of species. of the mesosome, which is bulbous, sinuate, During the period 1941-1945 concerted and not heavily sclerotized, fig. 77. investigations of the mosquito fauna of the This is a northern species, which we have southern areas of the United States led to taken in Illinois only in a tamarack bog the discovery of several species of Culex near Antioch. A single larva was taken hitherto recorded only from the Neotropical on the edge of the bog, June 4, 1943, Ross region. A digest of these and allied Nearc- Sz Sanderson; subsequent collecting during tic species is given in two papers, one by the same year failed to disclose additional W. W. Wirth (1945) and the other by ugust, 1947 ROSS: MOSQUITOES OF ILLINOIS 41

Figs. 79-81.—Larvae of Culex. A, apex of abdomen, lateral aspect; B, dorsum of head. In figs. 81 and 85, the ventral tufts are shown for both sides of the air tube. In other illustrations, tufts of only one side are shown. 42 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

82A P1 PIE NS

82B

83A QU1NQUEFASCIATUS

84A SALI MARIUS

Figs. 82-84.---Larvae of Culex. A, apex of abdomen, lateral aspect; B, dorsum of head, 1 ',gust, 1947 Ross: MOSQUITOES OF ILLINOIS 43

Pratt, Wirth & Denning (1945). These Comb scales forming a patch; body only papers supplement the work of Roth (1943) sparsely spiculose; upper head hairs on the Nearctic species of Culex. double or triple 8. peccator 5. Air tube very long and slender, fig. The genus is divided into many subgenera, 84, from six to eight times as long as width three of which are represented in Illinois. at end of pecten; tufts scattered and weak 5. salinarius KEY TO SPECIES Air tube either not more than five times LARVAE as long as wide, fig. 82; or with strong, 1. Antennal tuft near middle, fig. 79 clustered tufts, fig. 81 6 2. restuans 6. Air tube usually six times as long as width Antennal tuft considerably beyond middle, at end of pecten, sinuate but of almost fig. 80 2 uniform thickness throughout, and with

Fig. 85.—Ctilex erraticus, larva. A, apex of abdomen; B, dorsum of head.

2. Both pairs of head hairs long and single, all tufts near ventral margin, fig. 81.. an occasional hair double, fig. 80 6 tarsalis 1 apicalis Air tube usually three and one-half to five One or both pairs of head hairs either times as long as width at end of pecten, multiple, fig. 82, or very short, fig. 85 somewhat vasiform, definitely thickest 3 near end of pecten ; penultimate tuft 3. Lower head hairs long and single, upper distinctly more dorsal than, and out of short and double to multiple, fig. 85 4 line with, the others, fig. 82 7 Lower head hairs triple to multiple, similar 7. Air tube usually four to five times as long to upper head hairs, both pairs long, as wide; two basal pairs of hair tufts fig. 82 5 with a maximum of three or four Comb scales arranged in an irregular branches each, fig. 82 3. pipiens single or double row; body densely Air tube usually less than four times as spieulo-pilose; upper head hairs each long as wide, two basal pairs of hair with four or more branches; fig. 85... tufts with 5 to 10 branches each, fig. 83 7. erraticus 4. quinquefasciatus 44 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. I

FEMALES 3. Scales of veins R2 and R, very long and 1. Beak and hind tarsi with white bands; slender, fig. 87A, similar to scales on mesonotum with white lines, fig. 86,4 stem of R, (examination of wing mount ...... 6. tarsalis under a compound microscope is best Beak and hind tarsi entirely dark; meso- method for seeing this character) . . . .4 notum with pale dots but without white Scales of veins R2 and R shorter and lines on central portion ...... 2 wide, fig. 8713, contrasting with long, 2. Dorsum of abdomen with apical white slender scales on stem of R, 7 bands or apical lateral spots on some of -k Abdominal tergites with dingy basal bands the segments, and without basal bands. of yellowish or brownish scales, the I apicalis bands usually irregular and narrow... Dorsum of abdomen with basal bands but ...... 5. salinarius no apical bands...... 3 Abdominal tergites with bright and conspicuous basal bands of white scales, the central bands wide, fig. 8611, C...5 5. Abdominal dorsal white bands usually deep and crescentic, the bands not extending to edge of dorsum, fig. 86C...... 4. quinquefasciatus Abdominal dorsal white bands usually shallower, fig. 8611, or with posterior margin straight, extending to edge of dorsurn ...... 6 6. Mesonotum usually with a pair of central pale spots ...... 2. restuans Mesonotum always without any pale spots ...... 3. pipiens 7. Occiput with a large mesal triangle of narrow scales, the area between this triangle and eyes covered with wide, overlapping scales ...... 7. erraticus Occiput entirely covered with wide overlapping scales except occasionally for a narrow mesal line of narrow scales...... 8. peccator MALES 1. Basistyle globular and short; subapical lobe divided into two or three individ- Fig. 86.—Dorsum of Culex females. A, C. ual long stalks, figs. 94, 95 ...... tarsalis, thorax and abdomen; B, C. pipiens, Basistyle elongate, tapering at apex ; sub. abdomen; C, C. quinquefasciatus, abdomen. apical lobe only slightly, if at all, sub- divided, figs. 88-93 ...... 3 2. Dististyle narrow and only slightly curved ; subapical lobe with upper stalk slender, leaflet regular in shape and of moderate size, fig. 95 ...... 7. erraticus Dististyle wide, abruptly angled just beyond middle; subapical lobe with upper stalk stout, leaflet very large and with irregular outline, fig. 94... .8. peccator 3. Middle mesosomal plates armed with a cluster of stout sclerotized teeth, figs. 92, 93 ...... 4 Middle mesosomal plates not toothed, in some species not evident, figs. 88-91...... 5 4. Inner mesosomal plates with apical half expanded ; middle plates with basal projection, a, curved back and up under Fig. 87.—A, Cu/ex restuans, scales on wing teeth, fig. 92, and without a ventral vein L; B, C. erraticus, scales on wing vein blade paralleling inner plates ...... R„ and R2. 5. salinarius A ugust. 1947 Ross : MOSQUITOES OF ILLINOIS 45

\ 89A PIPIENS

88A API CALLS 89B . .96B QUINQUEFASCIATUS 88B

0 /( 91 B

RE ST UA NS

SALINARIUS

94A PECCATOR

95 C ERRATICUS

Figs. 88-95.—Culex, male genitalia. A, claspers, lateral aspect; B, mesosomal structures, dorsal aspect; C, ventral view of capsule. Abbreviations: s, apex of tenth sternite; r, basal arm of tenth sternite; m, middle and, n, inner mesosomal plates; a and h, as in text.

46 ILLINOIS NATURAL HISTORY SURVEY BULLETIN VOL 24, Ant. 1

Inner mesOsomal plates narrow and blade- tinct on the sixth. Legs with tibiae and tarsi like, apex curved laterad and paralleled entirely bluish brown, femora chiefly cream by a ventral blade of middle plates ; color with dark scaling on the upper surface. middle plates with basal projection, a, Wings entirely bluish-brown scaled. projecting only laterad, fig. 93 ...... MALE.—Similar to female. Palps long 6. tarsalis and with an extensive apical brush. Male 5. Inner mesosomal plates forming a V- or genitalia as in fig. 88. Basistyle slender, U-shaped structure, middle mesosomal plates also well developed, terminating with a distinct subapical lobe bearing a pair in a sickle-shaped process, figs. 89, 90 of long sinuate narrow processes and a pair 6 of shorter spurs. Tenth sternite with an Inner and middle mesosomal plates not apical row of truncate comblike setae. Mid- separate from each other, together rep- dle and inner mesosomal plates apparently resented by a single structure, figs. 88, fused to form a heavily sclerotized oval 91 7 structure beyond which project serrate 6. Rods of inner mesosomal plates divergent, edges of the ends of the middle plates. forming a V-shaped structure, fig. 89.. Of the Illinois species of Cu/ex, this is the 3 pipiens earliest. The larvae are to be found soon Rods of inner mesosomal plates conver- gent, forming a U-shaped structure, fig. after the early spring Aedes emerge; in 90 4 quinquefaseiatus southern Illinois in the latter part of April, 7. Inner mesosomal plates with apexes form- in northern Illinois in early June. Appar- ing a pair of stout rods curved laterad ently a cold water form, the species practi- at apex, fig. 91; brush of tenth sternite cally disappears during the hot summer bushy ...... 2. restuans weeks but reappears during the cooler weeks Inner mesosomal plates with apexes form- of late summer and early autumn. The ing a pair of round serrate lobes; the larvae show a decided preference for open entire structure forms a sclerotized marshes or moderately shaded pools with oval; brush of tenth sternite comblike, clear water. The species is found through- fig. 88 ...... 1. apical is out Illinois and has a wide distribution over most of North America. It is seldom Subgenus Neoculex Dyar noxious to man. Illinois Records.--Larvae, collected April This subgenus is characterized by the api- 17 to October 17, and adults, collected April cal abdominal bands on the abdomen. The 28 to October 6, are from Albion, Algonquin, male genitalia have the basistyles elongate, Alma, Belleville (usPHs), Cache, Cairo and the middle and inner mesosomal plates (usPHs), Calvin, Camp Ellis (usPHs), Camp are represented by a single structure, fig. 88. Grant (usPits), Carbondale, Carterville (usPHs), Central City, Chanute Field (usexs), Clinton, Cottage Grove, Crab Orchard Lake 1. Culex apicalis Adams (usPHs), Dixon Springs, Downs, Dupo, Durand, East St. Louis, East Dubuque, Ed- LARVA—Fig. 80. Head broad and short, wardsville, Effingham, Eichorn, Elsah, Ep- antennae long, with long apical setae and a worth, Giant City State Park, Gorham, Gossett, large tuft situated close to the apex. Upper Grafton (usPHs), Grand Tower, Granite City (usmis), Grantsburg, Great Lakes Naval and lower head hairs single and very long. Training Station, Halfday, Herod, Herrin, Eighth segment with a triangular comb of Joetta, Johnston City (usPHs), Kappa, Kar- about 50 scales. Air tube long and slender, nak, Keithsburg, Lake Villa, Lake Zurich, at least 10 times as long as width near the La Rue, Lawrenceville (usPHs), Marion, middle of pecten; pecten composed of 10 or Michael, Mill Shoals, Morris, Mount Carmel, more weak scales, beyond which are six or Mount Vernon (uspits), Mulberry Grove, Mun- seven ventral tufts. cie, New Boston, New Haven, Oakwood, FEMALE.—Length of wing 2.5 mm. Head Olney, Omaha, Palos Park, Pere Marquette and thorax almost entirely light brown. State Park, Princeton, Raymond, Rockville, Abdomen dark bluish brown with, usually, Rockwood, Rosecrans, St. Jacob, St. Joseph, Savanna, Scott Field (usPas), Seneca (usPHs), a narrow band of white scales along the Shawneetown, Springfield, Starved Rock State apical margin of each segment; these bands Park, Sugar Grove, Thomson, Urbana, Utica, may be interrupted in the middle of the seg- Vienna, Vol°, Wadsworth, Waltersburg, Ware, ments, or completely absent on the basal Wauconda, West Vienna, White Heath, Wil- four or five segments, but are always dis- low Springs, Yellow Springs, and Zion. ilugust, 1947 Ross: MOSQUITOES OFILLINOIS 47

Subgenus Culex Linnaeus throughout the summer and into early autumn. Although it has been recorded as In this subgenus the scales on vein 16 a painful biter, some observers believe that and It are slender and elongate, similar to it bites little, judged from our own experi- the scales on the stem of R2 and R ,3, fig. ence, this species is seldom annoying; cer- 87/. In the males, the genitalia usually tainly it is not such a persistent and vicious have the basistyle elongate and the middle biter as erraticus. Widespread throughout and inner mesosomal plates differentiated the eastern and central states from the as two pairs of processes. Atlantic seaboard to the Rocky Mountains, restuans extends southward to the Gulf. 2. Culex restuuns Theobald Illinois Records.—Larvae, collected April 17 to October 14, and many males and females, LARyA.—Fig. 79. Head moderately long. collected April 19 to November 23, are from Antennae shorter than head, each antenna Algonquin, Alton, Anna, Aurora, Belleville having short apical spines and a short tuft ( usPHs), Cahokia (usPHs), Cairo (usPHs), situated near middle. Preantennal tuft Calvin, Camp Ellis ( usmis), Camp Grant ( usPHs), Carbondale (usPHs), Carmi, short and multiple. Upper and lower head Carter- ville ( usPHs), Chanute Field (usms), Charles- hairs multiple and long. Eighth segment ton, Chester, Clinton, Cottage Grove, Crab with triangular comb of about 30 or 40 Orchard Lake (usPHs), Danville (usPHs), scales. Air tube elongate, nearly five times Durand, East Peoria (usPHs), East St. Louis, as long as greatest width, slightly enlarged Elk Grove, Epworth, Forest City, Forest Glen, near middle and tapering to apex; pecten Fox Lake, Galesburg (usPHs), George Field composed of 10 or more weak scales, beyond ( usPHs), Gorham, Grafton (usPlls), Grand which there are two long setae and a short Tower, Granite City (usetts), Great Lakes tuft on each side. Naval Training Station, Halfday, Havana, Herrin (usPHs), Hoopeston ( usPHs), Johnston FEMALE.—Length of wing 4 mm. Head City (usPHs), Kappa, Karnak, Keithsburg, and mesonotum bright brown. Mesonotum Lake Villa, La Rue, Lawrenceville ( usPHs), usually having an indistinct band of cream Marion (usPHs), Maroa, Milford (usPHs), scales around anterior and lateral portions Mount Vernon (usens), Mount Zion, Muncie, and around scutellum ; usually with a pair New Haven, Oakwood, Olney, Orland Park, of spots of cream color about the middle Palos Park, Pere Marquette State Park, Pitts- of the sclerite. Dorsum of abdomen bluish burg, Pittsfield, Princeton, Ravinia, Reynolds- brown, each segment with a basal bright ville, Ridge Lake, Rising Sun, Riverside, Rock- cream band which has a nearly straight pos- ford, Rock Island ( usPHs), Roxana, Russell- terior margin. Legs with tibiae and tarsi ville, Salem, Savanna ( usPfts), Scott Field ( usPHs), Seneca (usens), Shawneetown, Sko- entirely dark, femora cream, frequently with kie, Springfield ( usPits), Starved Rock State upper and outer areas dark. Wings entirely Park, Summerdale, Urbana, Vienna, Wads- dark scaled. worth, Waltersburg, Ware, Waterloo, White MALE.—Similar in size, structure, and Heath, Willow Springs, Winnetka, Wolf Lake, general color to female. Palps elongate, and Zion. with an extensive apical brush. Male genitalia, fig. 91, similar in shape of basistyle, 3. Culex pipiens Linnaeus subapical lobe, and dististyle to those of pipiens, fig. 89/. Tenth sternite with a LARVA.--Fig. 82. Head moderately wide, dense brush of narrow setae and with a with fairly long apical bristles and a thick moderately developed basal arm. Middle tuft situated near apex. Upper and lower and inner mesosomal plates apparently fused, head hairs multiple, as long as, or slightly each side with a broad base, with one or two longer than, the preantennal tuft. Eighth lateral bumps, and with a long apical proc- segment with triangular comb composed of ess curved sharply laterad at tip. 30 or 40 small scales. Air tube nearly four In Illinois this species is one of the most and one-half times as long as its width at common mosquitoes in unstocked fish ponds, end of pecten ; pecten composed of about 10 rain barrels, semidomestic water holes, and weak scales; between the end of the pecten pools of many types, especially those with and apex of tube are four tufts on each abundant humus. It is distributed over the side, one of them considerably more dorsad entire state. It occurs nearly as early in the than the others; these tufts are long and usu- season as apietilis and continues breeding ally composed of three hairs. 48 ILLINOIS NATURAL HISTORY SURVEY BULLETIN V ol. 24, Art.1

FEMALE—Length of wing 3.5 mm. Head ville (usPHs), Central City, Chanute Field dark bluish brown with scattered gray scales (usPHs), Charleston,'Chicago, Clinton, Cottage on dorsum. Mesonotum entirely brown. Grove, Crab Orchard Lake (usPHs), Danville Dorsum of abdomen bluish brown, each seg- (usPHs), Decatur (usPHs), Dwight, East St. Louis, Edwardsville, Elsah, Forest Glen, Gales- ment with a basal band of white scales; burg (usrus), George Field (usPHs), Gibson these bands moderately narrow, usually ex- City (usPHs), Grafton (usms), Granite City tending the full width of the segment and (usPHs), Great Lakes Naval Training Station, having the posterior margin irregular or Havana, Herrin, Hoopeston (uspHs), Johnston nearly straight across; the bands on seg- City (usPHs), Lawrenceville (usPHs), Marion, ments 3-6 should be used as examples. Legs Metropolis, Mound City, Mounds, Mount Car- with tibiae and tarsi black or dark, femora mel, Mount Vernon (usPHs), Palos Park, Peoria cream with dorsal or outer portions dark. (usens), Ravinia, Raymond, Rockford (usPHs), MALE.—Size, color, and general structure Rock Island (usPHs), St. Jacob, St. Joseph, Savanna (usPHs), Scott Field (usPHs), Seneca as for female. Palps elongate, with an (usPHs), Springfield (usPHs), Urbana, Vienna, extensive apical brush. Male genitalia, fig. Ware, Willow Springs, and Zion. 89: basistyle slender, its subapical lobe prominent, with a short leaflet and several bristles and spines; dististyle slender and 4. Culex quinquefasciatus Say curved. Tenth sternite with an apical brush of fairly short pointed spines, its basal arm LARVA.—Fig. 83. Very similar in size, slender and short, sometimes poorly devel- shape, and general structure to larva of oped and inconspicuous. Middle mesosomal pipiens. There is often considerable diffi- plate with two lobes, an irregular sclerotized culty in separating specimens of the two basal lobe, a, and a sickle-shaped apical lobe species. Material of quinquefasciatus col- that has a sclerotized apical edge and a lected in Illinois is distinguished by the fol- membranous area below this. Inner meso- lowing combination of characters: air tube somal plate composed of a single straight only about three and one-half times as long blunt blade on each side, the two forming -a as its width at end of pecten;_ tufts on air V-shaped structure. tube usually with four or more branches Known as the northern house mosquito, and usually markedly shorter than greatest this species is common over all of Illinois. width of air tube. The gills of both species The larvae frequent practically all types vary in length. of domestic and semidomestic pools, such as ADULTS.—Similar in almost all respects rain barrels, tar buckets, fish ponds, clogged to pipiens adults. The female usually has drains, and containers of various descrip- definite-shaped basal bands on the abdomi- tions. The adults are persistent hut wary nal tergites; in quinquef asciatus the bands biters, especially annoying at night in gar- are deeper than in pipiens and taper off com- dens or houses. The species occurs through- pletely at the edge of the dorsal aspect. out the season, from late spring until early Female specimens are encountered, however, autumn. In garden pools it frequently in which it is difficult to distinguish between occurs in company with restuans and quin- the two species either on this character or quefasciatus. It is one of the easier species any other. The male genitalia are very sim- to control by the use of clean-up measures ilar to those of pipiens in general conforma- directed against the semidomestic type of tion. Those of quinquefasciatus are dis- water containers in which this species breeds. tinguished as follows, fig. 90: the distal lobe, The northern house mosquito is widely b, of the middle mesosomal plates is larger distributed over most of the temperate and extends farther laterad than in pipiens; regions of the world having at least moder- and the arms of the inner mesosomal plates ate rainfall. In the eastern states it extends make a U-shaped structure with converging south of Illinois into the northern portion of arms (diverging arms in pipiens). the southern states. Cu/es quinquefasciatus, the southern house mosquito, occurs regularly in the southern Illinois Records.—Larvae, collected from third of the state but has been taken only May 3 to September 15, and many males and females, collected from May 6 to November sporadically northward. Light trap collec- 15, are from Algonquin, Belleville (usPHs), tions indicate that this species does not Cahokia (usPHs), Cairo (usPHs), Camp Ellis appear in numbers until July or August (usPHs), Carbondale (usPHs), Carmi, Carter- and usually disappears soon after the first

August, 1947 Ross: MOSQUITOES OF ILLINOIS 49 cool weather in September. The larvae extensive apical brushes. Genitalia, fig. 92: frequent the same types of domestic and basistyle long and slender, its subapical lobe semidomestic containers as those of pipiens with a leaflet and several bristles and spines. and the two species are usually represented Tenth sternite with a dense irregular apical in mixed cultures in Illinois. C. quinque- brush and with a long stout basal arm. fasciatus is distributed throughout most of Middle mesosomal plates with a dorsal the tropical and subtropical regions of the cluster of 8 or 10 stout teeth and a sharp world. The Illinois records appear to be on upturned stout ventral arm. Inner meso- the extreme northern edge of its North somal plates divergent, their apexes expanded American range, which extends southward and sinuate. to the Gulf of Mexico. Although the species occurs generally In much of the literature, this species has throughout Illinois, individuals are present been recorded under the name fatigans usually only in small numbers. Breeding Wiedemann. Edwards (1932) prefers to commences fairly early in the season and refer guillquefasciatus Say to the list of dubi- continues at a fairly uniform rate through- ously known names. Since guinquefasciatus out the summer and into the autumn. The has been used consistently as at present, larvae have been taken in a variety of habi- there seems no valid reason for discarding tats including swampy edges of lakes, oxbow this name in favor of fatigans; quinguefas- pools, marshes of various types, ponds and c'iatus was described in 1823, fatigans in cattle tracks, cattail bogs, stump holes, and 1828. polluted ditches. The females are said to Illinois Records.—Larvae, collected from bite readily, but in Illinois they are not suffi- September 15 to October 1, and adults, col- ciently abundant to be a nuisance. lected from June 17 to November 23, are from The species breeds in the eastern United Belleville (usPHs), Cahokia (usPHs), Cairo States westward into the Rocky Mountains, (usPHs), Carterville (usPHs), East St. Louis, and south to Florida and Texas. Edwardsville, Grafton (usPHs), Granite City Illinois Records.—Larvae, collected April (usPHs), Herrin (usPHs), Johnston City 16 to October 15, and adults, collected May 5 (usPHs), Marion (usPHs), Mount Vernon to November 23, are from Alton, Belleville (usPHs), Scott Field (usPHs), and Urbana. (usPHs), Cahokia (usPHs), Cairo (usPHs), Camp Ellis (uspus), Camp Grant (usPHs), 5. Cu/es salinarius Coquillett Carbondale (usPHs), Carmi, Carterville (usPHs), Chanute Field (usrus), Cottage Grove, Dupo, East St. Louis, Edwardsville, LARVA.—Fig. 84. Head moderately wide, Equality, Fox Ridge State Park, George Field antennae of moderate length, with long (usPHs), Gorham, Grand Tower, Grafton apical bristles and a stout tuft near apex. ( usPHs), Granite City (usPHs), Great Lakes Upper and lower head hairs long, with at Naval Training Station, Havana, Herrin, least four branches. Eighth segment with a Jacksonville, Johnston City (uspas), Karnak, triangular comb of about 50 small scales. Lake Glendale, La Rui, Lawrenceville (usPHs), Air tube very long and slender, about eight Marion, Maroa, Mount Vernon (usPits), Mun- times as long as greatest width, pecten com- cie, Olney, Orland Park, Palos Park, Ridge posed of about 10 weak scales and with sev- Lake, Rock Island (usPHs), Roxana, St. Charles ( usPHs), Savanna, Scott Field (usPHs), Seneca eral pairs of tufts irregularly placed between (usPtis), Springfield (usPHs), Urbana, Ware, end of pecten and apex of tube. Willow Springs, and Zion. FEMALE.—Length of wing 4 mm. Head and mcsonotum bright brown, dorsum of abdomen bluish brown with narrow basal 6. Cu/es tarsalis Coquillett bands yellowish scaled on each segment, the bands frequently indistinct on the basal two LARVA.—Fig. 81. Head moderately broad, or three segments and frequently broken up proportioned much as in pipiens, fig. 82B. with brownish scales, giving them a muddy Antennae elongate, with long apical bristles appearance. Legs with tibiae and tarsi , and with a tuft near apex. Both upper and entirely dark, femora mostly yellowish with lower head hairs multiple and about as long upper and outer surfaces frequently dark. as preantennal hair. Eighth segment with Wings entirely dark-brown scaled. a triangular patch of about 50 small scales. MALE.—Similar in size, color, and general Air tube slender, usually over six times as structure to female. Palps long, having long as its width at end of pecten; pecten 50 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 17 01. 24, Art. 1 composed of about 10 weak scales; beyond The species is said to hibernate as ferti- this are about five pairs of tufts arranged lized adult females; the males apparently very irregularly but all near ventral mar- die at the advent of winter. Breeding begin; the basal three pairs are long and each gins in early spring and continues until one has three to six hairs, the apical two autumn. short and usually having two to four hairs. The range of the species includes most of FEMALE.—Length of wing 4.5 mm. Beak the semiarid regions of the west coast and and palps dark brown, beak with a white the great plains. Illinois seems to be near band just beyond middle, palps with extreme the eastern edge of the range. Adults of this apexes tipped with white scales. Dorsum species have been found naturally infected of head with a mixture of brown and gray with the virus of western encephalomyelitis. scales. IVIesonotum brown with narrow The females, which attack men readily, are grayish-white lines as illustrated in fig. 86A. on the wing chiefly at dusk or after dark. Dorsum of abdomen brown with basal They invade houses often and are fierce and patches of white scales. Legs with posterior painful biters. aspects of femora and tibiae cream, anterior Illinois Records.—Larvae, collected June 11 aspects dark brown, each with a central to October 15, and males and females, collected stripe of white scales extending down the June 21 to October 28, are from Algonquin, middle of this brown area from base to Belleville (usPHs), Cahokia (usPHs), Camp apex, the white line on the anterior legs Ellis (usPHs), Carterville (usPlls), Chanute Field (usPHs), broken into a series of white bars; tarsi Des Plaines, East Peoria (usPHs), East St. Louis, Edwardsville, Fox dark bluish brown, all segments of hind Lake, Granite City (usPlls), George Field tarsi with a white ring at both base and apex (usPHs), Great Lakes Naval Training Station, of segment, tarsi of front and middle legs Greenville, Havana, Hoopeston (usPHs), John- with white bands indistinct on, or absent ston City (usPHs), Marion (usPHs), Milford from, the apical two or three segments. (uspHs), Savanna (usPHs), Scott Field (usPHs), Wings dark scaled except for a scattering Seneca (uspHs), Springfield, Urbana, Water- of white scales on the costal region of each. loo, and Zion. MALE.—In size, color, and general structure similar to female. Palps longer than Subgenus Melanoconion Theobald beak, apical two segments with a long brush. Genitalia, fig. 93: basistyle elongate, with This subgenus is characterized by the wide a pronounced subapical lobe bearing a small scales on veins R2 and R3, which are in leaflet, a pair of stout spurs and a pair of marked contrast with the long slender scales more slender spines. Dististyle curved and on Rs, fig. 87B. In the Illinois species, the narrow. Tenth sternite with a large apical males have the basistyle almost globular, lobe, the lateral series of teeth truncate and and the middle and inner mesosomal plates flattened. Middle mesosomal plates with not differentiated from each other. three distinct processes: (1) a large blunt basal tooth, (2) a series of five or six long 7. Culex erraticus ( Dyar & Knab) large sharp teeth, and (3) a curved ventral blade that is closely appressed to the inner LARVA.—Fig. 85. Head moderately wide. mesosomal plate. This last forms a long Antennae long, with long apical bristles and curved slender blade. with a long tuft situated near apex, prean- In the plains states this species occurs in tennal tuft long and dense, lower head hairs very large numbers; in Illinois it has been long, single, and bristle-like. Upper head taken in widely scattered localities over the hairs very short and multiple, with at least entire state and only rarely in large num- four and usually six hairs to each bristle. bers. The adults occur chiefly in middle Abdomen with most of the segments spicu- and late summer, with a few persisting into lose, having a covering of extremely fine early autumn. The larvae have been found spinules giving it a dense, pilose appearance. in a wide variety of situations, including Eighth segment with comb consisting of an hoof prints, pools, stream beds, marshes, irregular single or double row of 12 to 15 and backwaters. A colony at Cahokia, Illi- scales. Air tube only moderately long but nois, occurred in a drainage backwater hav- narrow, about six times as long as its width ing a very high pollution by sulfuric acid at end of pecten; pecten composed of about waste. 12 weak scales; beyond this are four or five August, 1947 Ross: MOSQUITOES OF ILLINOIS 51 pairs of long multiple tufts situated very tor and erraticus are distinct species. The close to ventral margin. name inhibitator should be applied to a FEMALE.—Length of wing 3.5 mm. Head, Santo Domingan species, whereas erraticus mesonotum, and dorsum of abdomen is the name to be used for this small dark almost entirely purplish-brown scaled; abdo- Illinois mosquito. men usually with narrow basal bands of Illinois Records.—Larvae, collected from cream scales, usually with brown scales June 29 to October 3, and males and females, intermingled so that the bands are indistinct collected from June 2 to November 4, are and muddy. Dorsum of head having a wide from Alma, Belleville (usPHs), Benton, Caho- kia (uspms), Cairo, Carbondale, Carterville triangular mesal area with narrow scales, (usPHs), Charleston, Cottage Grove, Coulter- the area between this and the eye covered ville, Crab Orchard Lake (usPi)s), Decatur with broad overlapping scales; these are in (usrns), East Hannibal, East Peoria (usPils), addition to the erect scales that stand up East St. Louis, IA-Aigemont, Edwardsville, like a comb above this area. Legs dark Effingham, Elsah, Fox Ridge State Park, George except for usually creamy portions of Field (usPHs), Gibsonia, Gossett, Grafton femora. Wings entirely dark scaled. ( usPHs), Grand Tower, Granite City (usPits), MALE.—SiZe, color, and general struc- Grayville, Greenville, Hannibal, Havana, ture as for female. Palps long, with exten- Herod, Herrin, Hull, Johnston City (t7sPHs) , sive apical brushes. Male genitalia, fig. 95: Karbers Ridge, Lake Glendale, Marion, Maroa, basistyle short and almost globular ; apical Momence, Mount Vernon, Neoga, Oakwood, Olive Branch, Omaha, Peoria (usptis), Pere lobe produced into three long stout stalks, Marquette State Park, Pike, Ridge Lake, the two lower ones each bearing a stout flat- Rock Island (usPHs), St. Joseph, Salem, Seneca tened process, the upper one bearing a leaf- (15sPlis), Springfield (usPris), Ware, West let and three spines; dististyle sinuate, with Vienna, and Willow Springs. the end ridged and produced into a pair of minute teeth. Tenth tergite bearing a row 8. Culex peccator Dyar & Knab of flattened teeth and a stout basal lobe of moderate length. Middle mesosomal plates LARvA.—Very similar to larva of errati- bladelike and each divided at apex into a cus, differing as follows: upper head hairs short sharp mesal point and a wider blunt short as in erraticus but only double or lateral triangle. Inner mesosomal plates triple; body only sparsely spiracular; comb apparently not differentiated. with the scales forming a definite patch Abundant and widespread in southern and rather than an irregular line. central Illinois, this species is a comparative ADULTS.—Similar in size, color, and gen- rarity in the northern part of the state. The eral structure to those of erraticus. Both larvae frequent marshy areas at the edges sexes differ in having almost the entire occi- of lakes, pools, and ponds in which there is put covered with appressed and overlapping abundant emergent vegetation. They are scales, at the most with a narrow mesal line especially numerous in ponds with growth of narrow scales. Males differ in characters of cattails and water primrose. In addition of the genitalia, fig. 94: the basistyle is nearly to ponds, they frequent vegetation-choked globular, as in erraticus, the subapical lobe shallows along the edges of sluggish streams is very definite, the leaflet large, irregular, and ditches. They are usually taken in com- and expanded, the stalks thicker and defi- pany with Anopheles, and frequently with nitely proportioned; dististyle very thick, Uranotaenia, also. In Illinois, adult emer- sharply bent at nearly a right angle with a gence begins in the southern part of the state, series of concavities and brushlike lines of usually early in June, and continues until minute setae. early autumn. The adults attack with per- Like the preceding, this species occurs sistence and inflict painful bites. throughout the southeastern states, where The species is widespread throughout the it is usually a rarity. In Illinois, we have southern states. Illinois is near the north- taken only a few records of the species and ern edge of its range. It was recorded from most of these are in the southern fifth of the Illinois by Matheson (1930) under the name state. The larvae presumably frequent inhibitator Dyar & Knab. At that time woodland pools with emergent vegetation. erraticus was generally considered a direct King, Bradley, & McNeel (1939) note that synonym of inhibitator. King & Bradley the larvae, when found, are almost always (1937) have shown, however, that inhibita- associated with those of apica/is.

52 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 'al. 24, tht. 1

Illinois Records.—CARBONDALE June 22-23, Ventral tuft situated beyond end of pecten, 194-2, 1 2 , 29 ; October 19, 1943, 1 3 . CARTER- fig. 98 3 VILLE: Aug. 13, 1942, 1 2. GOSSETT: June 3, 3. Gills budlike, much shorter than anal seg- 1942, Ross & Mohr, 3 larvae. GRANTSBURG: ment, fig. 98 4. sollicitans June 10, 1941, Ross & Mohr, 1 larva. LA RUE: Gills at least as long as anal segment, fig. Oct. 1, 1942, 1 . OLNEY: June 10, 1941, Ross 99, frequently very long and pointed at & Mohr, 1 larva. ScoTT FIELD: Sept. 10, 1942, tip, fig. 101 4 light trap, 1 2 . 4. Gills extremely long, two or three times length of air tube, and with prominent 9. AEDES Meigen tracheae, fig. 111; pecten with only a few scales 20. dupreei To this genus belong nearly half of the Gills shorter than air tube, without tra- Illinois mosquito fauna, with records for 21 cheae, fig. 106; pecten with about 15 scales species, which include nearly all of the truly 5 5. Air tube short, not more than two and nuisance species and both early spring and one-half times as long as wide, and pec- temporary summer pool species. One or ten with several widely detached teeth two of the species transmit mammalian dis- 5. nigromaculis eases. Either air tube over three times as long In all species of the genus, as far as as wide, or pecten without detached known, the eggs are laid on moist soil or teeth 6 humus, or just above the water line in tree 6. Comb consisting of about 12 scales or less holes or artificial containers. They hatch forming a single row, fig. 106 7 only after they have been flooded. Some Comb either consisting of 15 or more species, in which a desiccation and cold scales or forming a double row or tri- period is necessary for hatching, have only angular patch, fig. 108 8 7. Comb with a single generation per year, the adults 6 evenly spaced teeth; apico- dorsal tuft of anal segment represented emerging in early spring. Other species are by a pair of long, strong setae, as in intermittent breeders and usually have two fig. 106 22. implacabilis or three generations per year, depending on Comb with about 12 teeth forming an the rains. irregular line; apico-dorsal tuft of anal Certain taxonomic difficulties were encoun- segment many haired, fanlike, fig. 107 tered in studying the genus. The most 23 punctor important resulted in the discovery that in 8. Air tube with ventral brush two-thirds many of the species the head hairs of the distance from base to apex, fig. 108.... larvae were extremely variable, with the 14. trivittatus Air tube with ventral brush midway be- result that often in the then existing keys tween base and apex 6. mitchellae each side of the head of a single individual 9. Head with preantennal hair delicate and would key out to a different species. Fre- single, fig. 112; anal segment with pre- quently, on this same basis, specimens of a apical dorsal tuft only three-branched, pure culture would key out to several spe- but as long as apical tuft....2. aegypti cies. With the Illinois species it was possi- Head with preantennal hair divided into ble to circumvent this difficulty by introduc- a 4— to 15—branched tuft, fig. 113; anal ing new key characters especially concerning segment with preapical dorsal tuft 8— the relative positions of various stable hairs. to 15—branched, much shorter than api- Supplemental material regarding extra- cal tuft 10 limital species may be found in all of the 10. Pecten with one or more apical teeth comprehensive treatments of the family spaced fairly wide apart, appearing detached from row, figs. 101-103 listed under the heading "Literature" on 11 Pecten with all teeth close together and page 15. forming an even row, figs. 104, 105 16 KEY TO SPECIES 11. Head with lower head hair considerably LARVAE laterad of, and only slightly anteriad 1. Anal segment completely ringed by sclero- of, upper head hair, fig. 100 12 tized plate, fig. 96 2 Head with lower head hair only slightly Anal segment with sclerotized plate not laterad of, but considerably anteriad meeting on venter, frequently forming of, upper head hair, fig. 102 13 only a dorsal saddle, fig. 99 9 12. Antennae fairly thick at base and long, 2. Pecten extending beyond ventral tuft, tuft beyond middle, fig. 100; upper and fig. 96 21. fulvus pallens lower head hairs double, occasionally

August, 1947 ROSS: MOSQUITOES OF ILLINOIS 53

TRI SERIATUS

Figs. 96-101.—,4edes larvae; .4, apex of abdomen, lateral aspect; B, dorsum of head. Inset are details of pecten and comb scales. On these and succeeding larval head drawings of Aedes, the mouth brushes are omitted. 54 ILLINOIS NATURAL HISTORY SURVEY BULLETIN T'ol. 24, 'frt. 1

Ii 10.3A 102 B E XCRUC IANS

102A VEXA NS

- 105 A CA NA DENS IS

104 A

ST IMU LAWS 105 B

Figs. 102-105.—A edes larvae; A, apex of abdomen, lateral aspect; B, dorsum of head. Inset are enlarged drawings of pecten and comb scales. ugust, 1947 Ross : MOSQUITOES OF ILLINOIS 55

106 A IMPLACABILIS

107A STICTICUS

109A F ITC HI

Figs. 106-110.—Aedes larvae, apex of abdomen. Al] are the lateral aspect except fig. 110B, which is the ventral aspect of A. spencerii showing one or two anal hair tufts anterior to the barred area at base of gills. 56 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. I

III B

DUPREE!

II2B

113A

GROSSBECKI 11 3 B

Figs. 111-113.—Aedes larvae; A, apex of abdomen, lateral aspect; B, dorsum of head. Inset are enlarged drawings of pecten and comb scales. (Fig. 111 redrawn from llyar.) ugust, 1947 ROSS: MOSQUITOES OF ILLINOIS 57

one of the four triple; clypeal bristles nae shorter, with a shorter tuft, fig. moderately far apart 15. aurifer 113 20 Antennae not enlarged at base, tuft below 20. Air tube five times as long as width at middle, fig. 101; upper and lower head middle of pecten, tapering markedly, so hairs triple to multiple, at least two of that apex is about half width of base, the four with four to six branches; fig. 109.4, its apical spine long and dark clypeal bristles much closer together. .. 11. fitchii 7. cinereus Air tube at most four times as long as 13. Air tube five times as long as width at width at middle of pecten, tapering less, middle of pecten, its ventral tuft very so that apex is about three-quarters long, fig. 103 8. excrucians width at base, its apical spine short and Air tube not more than four times as long inconspicuous, fig. 107 21 as width at middle of pecten, its ven- 21. Sclerotic plate of anal segment only slightly tral tuft frequently short, fig. 102...14 longer than deep, extending more than 14. Upper and lower head hairs single ; anal three-quarters distance down sides of segment with only one or two tufts ante- segment, fig. 107; air tube with ventral rior to apico-ventral barred area, fig. tuft only about half as long as tuft 110 19. spencerii posterior to comb 18 sticticus Upper and lower head hairs double to Sclerotic plate of anal segment much quadruple; anal segment with several longer than deep, extending only one- tufts anterior to barred area, fig. 102 half or two-thirds distance down sides 15 of segment, fig. 104; air tube with ven- 15. Lateral comb consisting of more than 20 tral tuft about as long as tuft posterior scales in a triangular patch to comb 22 9. flavescens 22. Lower head hairs usually single; protho- Lateral comb consisting of 10 to 15 scales racic hairs 4 and 7 single ; ventral tuft in an irregular single or double row, of air tube usually with three or four fig. 102 3. vexans hairs 10 stimulans 16. Gills budlike, much shorter than anal seg- Lower head hairs usually double or triple; ment, as in fig. 98A prothoracic hairs 4- and 7 usually double ; 16. dorsalis ventral tuft of air tube usually with Gills long, either tapering at apex, fig. five to eight hairs 13. grossbecki 104, or sausage shaped, fig. 99 17 FEMALES 17. Lateral comb of segment 8 forming a single row or an irregular double row 1. Tarsi with white rings, figs. 127-132...2 of about 10 to 15 large well-spaced Tarsi without white rings, figs. 125, 126 teeth, fig. 99 1. triseriatus 13 Lateral comb forming a somewhat tri- 2. Tarsi with narrow rings at both ends of angular patch containing 20 or more some segments, fig. 132 3 teeth, figs. 104, 109 18 Tarsi each with a ring at only one end 18. Both upper and lower head hairs with of a segment, fig. 130 4 four or more branches, short, similar in 3. Wing scales uniformly dark length and appearance to preantennal 17. canadensis hair ; clypeal hairs only about half as Wing scales mostly white with a small far apart as upper head hairs, fig. 105 mixture of black scales. . . .16. dorsalis 17. canadensis 4. Proboscis dark with a definite white band, Either upper or lower head hairs with fig. 35 5 only three branches or less, much longer Proboscis nearly uniformly colored 7 than preantennal hair, or clypeal hairs 5. All wing scales dark ; hind basitarsus about as far apart as upper head hairs, black with a single basal white band, fig. 97 19 fig. 131 6. mitchellae 19. Lower head hairs situated considerably to Some wing scales black, some white, giv- the side of, and only slightly anterior to, ing a spotted appearance; hind basi- upper head hairs, the upper hairs usu- tarsus frequently with a middle yellow- ally with five branches or more; anten- ish band in addition to basal white nae very long, three-quarters length of band, fig. 130 6 head, with antennal tuft very long, 6. Abdomen with extensive dorsal areas of fig. 97 12. thibaulti cream or tawny scales and small lateral Lower head hair, almost directly anterior areas of white scales, the two colors to, and only slightly laterad of, upper definitely contrasting 4. sollicitans head hairs, the latter only rarely with Abdomen with both dorsal and lateral as many as four or five branches; anten- pale scales white 5. nigromaculis 58 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art.

7. Mesonotum black with lyre-shaped silver 8. White tarsal rings narrow, fig. 127 ...... markings, fig. 114 ...... 2. aegypti ...... 3. vexans Mesonotum otherwise, figs. 115-123, never White tarsal rings wider, figs. 124, 130 with extensive silver lines ...... 8 ...... 9

Li 117

118

I26 , 121 1 22 127

128 4-- .0" 4.-- 29

12.3

Color Patterns of Female Aedes

Fig. 114.—A. aegypti, dorsum of thorax and Fig. 121.-3. triseriatus, dorsum of thorax abdomen. of light phase. Fig. 115.-1. trivittatus, dorsum of thorax Fig. 122.-3. thibaulti, dorsum of thorax. and abdomen. ( After King, Bradley, & McNeel.) Fig. 116.—A. sticticus, dorsum of thorax Fig. 123.—A. aurifer, dorsum of thorax. and abdomen. Fig. 124.-3. grossbeeki, hind leg. Fig. 117.—A. spencerii, dorsum of abdomen. Fig. 125.—A. sticticus, hind leg. Fig. 118.—A. grossbecki, dorsum of tho- Fig. 126.—A. triseriatus, hind leg. rax and abdom en. Fig. 127.—A. qyxans, hind leg. Fig. 119.—A. dorsalis, dorsum of thorax and Fig. 128.—A. aegypti, middle leg. abdomen. Fig. 129.—A. aegypti, hind leg. Fig. 120.—A. triseriatus, dorsum of thorax Fig. 130.—A. sollicitans, hind leg, and abdomen. This figure illustrates dark Fig. 131.—A. mitchellae, hind tarsus. phase of thoracic pattern. Fig. 132.—A. dorsalis, hind tibia and tarsus. . Jugust, 1947 Ross; MOSQUITOES OF II-Am:ors 59

9. All veins of wings with rows of very wide fig. 116, without mesal or apical stripes scales, fig. 169; mesonotum as in fig. 118, 18. sticticus with a large central black spot enlarged Abdomen with light stripes basal, apical posteriorly 13. grossbecki and mesal, narrowest on basal segments Some veins with rows of only long narrow and almost covering the apical segments, scales, fig. 168; mesonotum marked oth- fig. 117 ...... 19. spencerii erwise 10 18. Scales of postero-lateral lobes of prono- 10. Abdomen entirely covered with yellowish turn white and wide, markedly over- scales, without banding ; mesonotum lapped to form a solid shingled area, entirely yellowish 9. flavescens fig. 170, very similar to scales of meso- Either abdomen with decided banding or pleurae 1. triseriatus mesonotum with a pattern of gray or Scales of postero-lateral lobes of prono- reddish brown 11 trim long and narrow, only half as wide 11. Lower part of mesepimeron with three to as mesopleural scales, tawny or yellow- five fine long bristles; mesonotum fre- ish in color and not solidly shingled, fig. quently patterned with light gray brown, 171, markedly contrasting with scales but occasionally reddiAl brown of mesopleurae ...... 19 10. stimulans 19. Mesal dark mark of mesonotum w:th ante- Lower part of mesepimeron with none to rior portion narrow, suddenly widened two fine long bristles; mesonotum always beyond middle to include nearly full predominantly reddish brown 12 width of mesonotum, fig. 122; antero- 12. Mesonotum with a fairly narrow reddish- lateral areas bright grayish white brown stripe, flanked with white or 12. thibaulti cream; one or two lower mesepimeral Mesal dark mark of mesonotum with ante- bristles usually present 11. fitchii rior part wider, widening gradually to Mesonotum with reddish-brown central posterior margin, fig. 123; lateral areas area larger and not well defined ; no grayish, shading to a golden tint where lower mesepirneral bristles present.... they merge with mesal dark area.... 8. excrucians 15. aurifer 13. Mesonotum with a definite mesal silvery 20. Integument and scaling entirely bright triangle, flanked with dark areas golden yellow, except a few black-scaled ...... 20. dupreei areas 21. fulvus pallens Mesonotum without a mesal silvery tri- Integument dark brown to black, with angle, usually with a rnesal dark area few or no yellow scales 21 flanked with light areas, figs. 115, 121 21. Maxillary palps with apical segments only ...... 14 slightly longer than basal segments; 14. Mesonotum with very dark or black mesal wing at most 4.3 mm. long; abdomen area flanked by gray or silvery areas, with very narrow cream basal bands on figs. 115, 121 ...... 15 dorsum but with all of ventral part of Mesonotum brown or yellow, often uni- tergites cream 7. cinereus form in color, sometimes with mesal Maxillary palps with apical segments area reddish brown and lateral areas twice as long as basal segments; wing light golden brown 20 over 4.8 mm. long; abdomen either with 15, Central stripe of mesonotum narrow, wide basal bands, or ventral part of tapering posteriad, well defined, fig. 115 tergites with considerable areas of dark ...... 14. trivittatus scales 22. implacabilis; 23. punctor Central stripe either wider posteriad, fig. 121, or parallel sided, fig. 116 ...... 16 MALES 16. Central stripe of mesonotum parallel sided, 1. Dististyle inserted before apex of basi- sometimes with a pair of detached short style, the portion beyond the dististyle dark stripes along posterior half, fig. forming an apical cone, fig. 135 ...... 116; abdominal tergites with complete ...... 7. cinereus basal or mesal white bands 17 Dististyle articulating as extreme apex of Central stripe of mesonotum much nar- basistyle, fig. 133 ...... 2 rower anteriad, usually widened pos- 2. Dististyle wide near apex, terminating in teriad to almost the full width of the a sharp projection that is nearly as long mesonotum, figs. 121, 123, abdominal as terminal spine ; claspettes forming a tergites mostly blue black, with lateral small, bushy lobe, fig. 133. . . .3. vexans white spots on some segments, but with- Dististyle narrow at apex, tipped by ter- out bands, fig. 120 ...... 18 minal spine, fig. 134 ...... 3 17. Abdomen with light stripes narrow, regu- 3. Claspettes absent, fig. 134 ...... 2. aegypti lar and basal, widest on basal segment, Claspettes present, figs. 136-158 ...... 4 60 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, "frt. 1

134 AEGYPTI

136 137 TRISERIATUS /MITGHELLAE 135 CFNEREUS

138 • 139 1 40 SOLLICITANS THIBAULT1 ->" CANADENSIS

Figs. 133-140.—Aedes, male genitalia, ventral aspect; .4, mesal aspect of hastistyle; db, dorsal brush; inset is claspette, lateral aspect. (Figs. 133, 134 after Matheson.) ug ust, 1947 Ross: MOSQUITOES OF ILLINOIS 61

141 142 1NTRUDENS

144 ATLANTICUS

Figs. 141-146.-2/edes male genitalia, ventral aspect. A, basistyle, mesal aspect; B, enlarged detail of basal lobe, ventral aspect; C, claspettes, dorsal aspect; inset is claspette, lateral aspect. 62 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, /ht. 1

- A.--:- \ ......

, ±-,------(..---- 1 47 DOPREEI

148 sricTicus q 1 49 SPENCERII

•A TRW ITTATU.3

152 153 - FLAVESCENS . . STIMULANS

Figs. 147-153.—.3edes male genitalia, ventral aspect. .1, basistyle, mesal aspect; basal lobe, 13, ventral aspect; D, basal lobe, posterior aspect; inset is claspette, lateral aspect and in figs. 148 and 149 a detail of its apex. ugust, 1947 Ross: MOSQUITOES OF ILLINOIS 63

- 154 FITCHII A EXCRUCIANS

PUNCTOR 157 GROSSBECKI

Figs. 154-158.—Aedes male genitalia, ventral aspect. A, basistyle, mesal aspect; C, claspettes, dorsal aspect; D, basal lobe, posterior aspect; E, basistyle, ventro-lateral aspect silhouette; inset, claspette, lateral aspect.

64 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

4. Basistyle without apical lobe, figs. 136- 14. Appendage of claspette wide, its lower 138 5 basal corner produced; mesa] aspect of Basistyle with apical lobe definitely devel- apical lobe long and narrow, fig. 149.. oped, figs. 139, 140, or represented by a ...... 19. spencerii mass of long setae, figs. 141, 142 ...... 7 Appendage of claspette narrower, its 5. Basistyle with a thick brush of setae (db) lower margin almost confluent in out- on dorsal side, fig. 137; basal lobe with line with claspette ; mesal aspect of api- a large area of setae... . 1. triseriatus cal lobe shorter, decidedly ovate, fig. 148 Basistyle without a brush of setae on dor- 18. sticticus sal side, but with a definite brush form- 15. Basal lobe without macrochaetae, having ing the basal lobe, figs. 136, 138 ...... 6 only abundant short setae, fig. 155.... 6. Basal lobe a distinct, raised prominence; ...... 8. excrucians basistyle considerably widened at basal Basal lobe with at least one conspicuous lobe, fig. 136 ...... 6. mitchellae macrochaeta or a group of long setae, Basal lobe represented by only a slightly fig. 154 ...... 16 raised disclike area; basistyle only 16. Head of claspette produced backward in- imperceptibly widened at this point, fig. to a sharp basal barb, fig. 151 ...... 138 ...... 5. nigromaculis ; 4. sollicitans ...... 14. trivittatus 7. Apical process of claspette massive and Head of claspette without a barb, fig. 152 contorted, fig. 139, the contorted por- ...... 17 tion thin and pale 12. thibaulti Apical process of claspette forming a nar- 17. Basal lobe composed primarily of an area row blade, which may be straight, fig. of short setae forming the basal portion 140, curved, fig. 143, or barbed, fig. 141 of the mesal face of the basistyle, figs...... 8 152, 153 ...... 18 8. Basistyle with a dense patch of long setae Basal lobe represented by a distinct lobe at apex; basal lobe forming a fiat scle- projecting mesad from the basistyle, rite on mesal face, with a single long figs. 154, 156 ...... 19 dorsal spine, fig. 141 15 aurifer 18 Area comprising basal lobe long and tri- Basistyle without a dense apical patch of angular, its basal spine very large, fig. long spines, but with a well-developed 152; appendage of claspette fairly short apical lobe; basal lobe otherwise, either 9. fiavescens projecting, or with a large ventral spine, Area comprising basal lobe shorter, its or without a spine, sometimes with a lower portion somewhat projecting, its cluster of long setae 9 basal spine only moderately large, fig. Apical lobe with a large dense patch of 153; appendage of claspette very long spatulate setae, fig. 140. .17. canadensis and slender ; a membranous "island" Apical lobe with setae all narrow and above macrochaeta ...... 10. stimulans hairlike, figs. 143-158 ...... 10 19. Apical lobe short, appendage of claspette 10. Apical lobe of basistyle very long, a dis- elongate with a narrow necklike base, tinct angulation near middle of basi- fig. 157 ...... 13. grossbecki style, fig. 143; integument of almost Apical lobe very long, fig. 156, or append- entire body yellow. .21. fulvus pallens age of claspette without a basal neck, Apical lobe either short, fig. 144, or with- fig. 154 ...... 20 out an extra angulation, fig. 145; integ- 20. Basal lobe with membranous, setiferous ument chiefly dark brown or black 11 portion hidden behind sclerotized ven- 11. Basal lobe with two macrochaetae and tral shoulder, fig. 158, which projects many small setae, those near the macro- ventro-mesad ...... 22. implacabilis chaetae minute, fig. 145...16. dorsalis Basal lobe with membranous, setiferous Basal lobe at most with only one macro- portion well exposed from ventral aspect, chaeta, sometimes with some of the and without a projecting ventral shoul- other setae very long, fig. 147 ...... 12 der, figs. 154, 156 ...... 21 12. Basal lobe triangular and appearing de- 21. Basal lobe with sparse and moderately tached, joined to basistyle by only a nar- short setae, without a sclerotized band row sclerotized strip, figs. 147-149 ... 13 along the dorsal and mesal periphery; Basal lobe forming a solid part of the apical lobe with abundant setae on basistyle ...... 15 mesal face, fig. 156 23 punctor 13. Apical lobe small, fig. 147, with a few Basal lobe with abundant longer setae projecting setae along its mesal margin which form a thick brush, and with a 20. dupreei sclerotized collar around the dorsal and Apical lobe large, fig. 148, with numerous mesal periphery, fig. 154; apical lobe appressed setae along its mesal margin with a few long setae on mesal face... 14 11. fitchii 'oust. 1947 Ross: MosourroEs OF lLuNois 65

THE SUBGENERIC UNITS Either segment much longer than high, fig. 167, or sternite with nearly straight An investigation of characters of the apical margin, projecting markedly be- female genitalia indicates that the subgenera yond tergite, fig. 162; cerci frequently represented in the Illinois Aedes fauna are long, fig. 167, and postgenital plate usu- readily segregated on these characters. In ally with only a shallow cleft. Con- tains most of the Illinois species of the those subgenera in which we have more than genus ...... Ochlerotatus one species, either no differences were found among the included species (in the case of Subgenus Finlaya Theobald Taeniorhynchus), or the differences observed among the various species were so slight and 1. Aedes triseriatus (Say) of such a comparative nature that it was LARVA.—Fig. 99. Head slightly longer impractical to use them as a basis for identi- and more rounded than in most other mem- fication. These findings follow closely those bers of the genus; upper head hairs long, of Gjullin (1937), who treated western slender, and single or double; lower head species of the genus. hairs shorter, double to quadruple, and having between them a pair of distinct pluinose DIAGNOSIS OF SUBGENERA REPRESENTED tufts. Eighth segment with comb forming IN ILLINOIS a single row varying from a regular one (BASED ON FEMALE GENITALIA) composed of 6 or 8 teeth to a dense, irregu- 1. Postgenital plate elongate, extending three- lar row consisting of 10 to 14 teeth. Air fourths distance to tip of cerci ; eighth tube about three times as long as wide, both segment large and well sclerotized, with the dorsal and ventral margins curving to short basal membrane, fig. 160. Sole form a tapered apex; hair tuft long, single Illinois species, triseriatus. . . Finlaya or double, and situated beyond pecten; pec- Postgenital plate shorter, its tip not reach- ten with 15 to 20 fairly even and quite reg- ing half the distance to tip of cerci, fig. ularly spaced, closely set teeth. Anal seg- 159 ...... 2 ment with dorsal plate covering only the 2. Apical margin of eighth sternite with a deep mesal cleft or incision, figs. 159, dorsal half of the segment and bearing a 163 ...... 3 multiple tuft at its postero-ventral corner; Apical margin of eighth sternite with only anal gills rounded at apex, short, the ven- a shallow indentation, fig. 164, or trans- t:A-al pair shorter than dorsal pair. verse, fig. 167 ...... 4 FEMALE.—Length of wing 4 mm. Beak 3. Cerci little longer than ninth tergite; post- and palps black scaled; back of head silver genital plate with rounded apex ; eighth scaled. Mesonotum with a black central segment nearly as high as long, fig. 163. portion and silver lateral areas forming a Sole Illinois species, aeqypti ...... pattern shown in figs. 120, 121; there is con- ...... Stegomyia Cerci nearly twice as long as ninth tergite; siderable variation in the shape of these postgenital plate with apex notched ; markings. Pleural areas with patches of eighth segment nearly twice as long as very dense silvery scales. Abdomen with high, fig. 159. Sole Illinois species, dorsum chiefly blue-black scaled, segments vexans ...... Aedimorphus 4-7 with lateral patches of white scales 4. Eighth tergite and sternite almost entirety which are smallest on 4, increase posteriorly membranous, with minute sclerotized and usually form a solid white band on 7, spots at bases of some setae; apex of venter conspicuously banded with black and eighth sternite forming a moderately sclerotized "flap," which is slightly in- white, the white predominating. Legs with cised on meson, fig. 164. Only Illinois tibiae and tarsi blue black, femora with species, soilicitans and mikkellac ...... basal half cream, apex blue black, sometimes ...... Taeniorhynchus the anterior face almost entirely blue black. Eighth segment moderately and uniformly Wings entirely dark scaled. sclerotized throughout the principal MAI.E.—Color identical with that of sclerites ...... 5 female. Palps extremely long, projecting 5. Eighth segment nearly as high as long, beyond beak. Male genitalia, fig. 137, char- the sternite with its apical margin sinuate and not projecting beyond the ter- acterized as follows: basistyle without defi- gite ; cerci short; postgenital plate with nite apical or basal lobes, the meso-basal a deep cleft, fig. 166. Sole Illinois spe- portion of the ventral aspect having a large cies, cinerens ...... Aedes loose brush and dorsal portion having a 66 ILLINOIS NATURAL HISTORY SURVEY BULLETIN J ol. 24, Art. 1 conspicuous tuft near middle of rnesal edge. short, usually quadruple, situated just be- Claspettes prominent, the base stout and yond end of pecten; pecten consisting of a short, the apical process long and slightly close regular row of small teeth. Anal seg- curved at apex. ment with a ventral membranous strip Breeding primarily in water in tree hole between edges of sclerotized band; each pre- cavities, this species is distributed over the apical dorsal tuft with three to four fila- entire state. The adults are sharp biters ments, apical dorsal tufts each with two, but apparently do not wander far from the the filaments of both of about equal length; woods in which occur their breeding places. anal gills sausage shaped and about as long In periods when the rainfall and sap flow as siphon. refill the tree holes frequently during the FEMALE.—Figs. 114, 128, 129. Length of summer, this species breeds almost continu- wing 3.5 mm. Entire body and appendages ously. Development of the larvae is very clothed with very dark brown or black scales slow compared to that of species which having many small and narrow silver spots occur in ground pools. The few observa- and stripes, as follows: head with spots at tions we have made indicate that the larvae apex of palps, base of antennae and other may require nearly a month during the sum- places; mesonotum with two conspicuous mer to reach maturity. The species hiber- lateral stripes curved so that both form a nates in the egg stage. lyre-shaped pattern, with fainter mesal Recorded from the Chicago area by Ger- stripes and three white spots on scutellum; hard in 1910, the species was listed as wide- pleurae with several patches of silver scales; spread throughout the state by Matheson abdomen with a narrow white basal band in 1930. on each segment, with a conspicuous large Illinois Records.—Larvae, collected May 16 silver spot on the lateral portion of each ter- to September 16, and adults, collected May 10 gite, and with the sternites forming a nar- to October 22, are from Belleville (usPHs), row whitish area between these; hind tibiae Cahokia (usPHs), Camp Grant (uspns), Camp with a broad white band at the base of each Ellis (usPHs), Chicago, Carterville (usPHs), segment, middle and front legs with white Crab Orchard Lake (usPHs), Danville, Des bands on only the basal two segments; tibiae Plaines, Dongola, Dubois, East St. Louis, black; femora with small white kneecaps Elsah, Epworth, Glencoe, Gorham, Great Lakes and stripes of silver scales along the anterior Naval Training Station, Havana, Homer, Johnston City (usPHs), Kappa, La Rue, Law- faces and much of the ventral faces. Wings renceville (usPFis), Mahomet, Marion (usPHs), entirely dark scaled. Mascoutah, Mount Carmel, Mount Vernon MALE.—Similar in size and color to female (usPHs), Muncie, Oak Park, Oakwood, Onarga, with the exception of the palps, which are Pike, Pulaski, Ravinia, Rising Sun, Rockford very long, have no apical brushes, and have (usPHs), Roxana, St. Jacob, Scott Field well-defined conspicuous white bands at the (usPHs), Springfield, Starved Rock State Park, base of each segment. Male genitalia, fig. Urbana, Ware, Weldon Springs, and White 134, with very broad robust basistyle, disti- Heath. style terminal and simple, and claspettes completely absent. Subgenus Stegomyia Theobald This species, the widespread yellow- fever mosquito of the South, has been taken 2. Aedes aegypti (Linnaeus) at only one or two isolated points in Illinois. LARVA.—Fig. 112. Head somewhat oval; In this state it seems to be restricted to iso- preantennal hair and upper and lower hairs lated small populations that occur as adven- all very delicate, long, and single; upper tives. Apparently none of the introductions hairs almost directly on a line between the has persisted longer than a single summer. two preantennal hairs; lower hairs anterior The records listed below from Edwardsville to upper hairs but situated close to anterior appear to be based on the introductions of margin of head and with a pair of delicate adults with merchandise; probably no breed- tufts between them. Eighth segment with ing or colonization resulted. comb consisting of a single arcuate row of Apparently this mosquito, one of the most about 10 toothed scales. Air tube short and important vectors of yellow fever, does not relatively stout, about two and one-half occur in Illinois naturally and is not able to times as long as wide and with its ventral establish itself permanently even when intro- margin slightly concave; hair tuft fairly duced. August, 1947 ROSS: MOSQUITOES OF ILLINOIS 67

159 B P VEXANS 159 A

161 B ATROPALPUS

- 160 A

TRISERIATUS

AEOYPTI

165 C FULVUS : • I64 .B

164 A SOLLICITANS

166 A CINEREUS

CANADENSIS I67A 167B I67C

Fi:s. 159-167.-4edes female genitalia. .4, lateral aspect; B, ventral aspect ; C, dorsal aspect. Abbreviations: c, cercus ; p, postgenital plate; s, sternite; t, tergite. Fig. 167B shows only the postgenital plate. 68 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

Illinois Records.—BEr.r.Evn.t.E: Aug. 6, 1942, basal swelling; dististyle with the apical C. J. Rohde, I y (uspus) ; Aug. 26, 1942, spine prominent and arising a short distance chicken coop, 1 y (uspHs). EDWARDSVILLE : from the apex, this spine and the pointed Sept. 24, 1943, biting in shop, Ross & Sander- apex usually appearing as a fork; claspettes son, 4 ; Oct., 1943, Ross & Sanderson, 1 8 , 6 y short and surmounted by a tuft of short WATERLOO: Sept. 14, 1942, J. Williams, 1 ( usPHs). setae. The commonest mosquito in Illinois in point of numbers throughout the warmer Subgenus Aedimorphus Theobald months of the year, Aeries vexans has a range that blankets the entire state. It is a 3. Aedes vexans ( Meigen) vicious biter and breeds in a wide variety of LARVA.—Fig. 102. Head with upper hairs temporary pond situations. Especially abun- sometimes triple, sometimes quadruple, dant after the summer rains, when it lower hairs double or triple, both of mod- emerges in clouds from many types of rain erate length and without tufts between pools and the flooded edges of marshes, them. Eighth segment with comb variable, vexans is the greatest mosquito nuisance in ranging from 6 to 12 teeth arranged in a the state. To date the species is not known scattered single row or an irregular double to transmit human diseases. row. Air tube three and one-half to four There is a great deal of literature on this times as long as wide; hair tuft short, usu- mosquito. Formerly it was recorded as ally quadruple, situated well beyond the sylvestris Theobald. Holarctic in distribu- pecten; pecten with 17 to 25 teeth, the basal tion, it does not extend in numbers into the teeth small, one to three apical teeth very extreme southern United States but is abun- large, widely separated from the remainder dant at least as far south as southern Illi- of the pecten, and, if more than one, from nois. each other. Anal segment with sclerotized The species may have several generations ring not complete ventrally; anal gills each year. The first brood of adults typi- longer than ring, tapering gradually and cally emerges in early spring, a week or so pointed at apex, sometimes nearly as long after emergence of canadensis and stieticus. as the air tube. Illinois Reeords.—Larvae, collected April 3 FEMAI,E.—Length of wing 4.5 mm. Head to September 9, and many males and females, variegated with gray and brown. palps collected April 5 to October 26, are from Algon- mostly brown-and-black scaled, with a small quin, Allendale, Altamont, Amboy, Antioch, patch of white scales at apex. Mesonotum Arcola, Baker, Beach, Belleville ( usPHs), Ben- almost uniformly dark-brown scaled except ton, Bensenville, Billett, Bishop, Bourbonnais, Cache, Cahokia ( usPHs), Cairo, Calvin, Camp for irregular posterior and lateral patches Ellis (usPHs), Camp Grant (usPHs), Carbon- of gray scales. Abdomen with dorsum con- dale ( usPHs), Carterville ( usPHs), Cary, spicuously banded, each segment with a Casey, Cave-in-Rock, Central City, Champaign, basal white band and an apical bluish-brown Channel Lake, Chanute Field (uspHs), Charles- band; the apical tergites frequently have an ton, Chebanse, Chemung, Chester, Chicago, additional narrow white band of scales and Cordova, Danville, Darwin, Del Rio, Des the basal white bands are usually very nar- Plaines, Downs, Duncans Mills, Dupo, East row on the meson; venter of abdomen Dubuque, East Moline (usnfis), East Peoria almost entirely white scaled. Legs, fig. 127, ( usPHs), East St. Louis, Edwardsville, Effing- ham, Eichorn, Eldorado, Elgin, Elizabethtown, with tarsi black, each segment with a basal Elsah, Epworth, Farmer City, Fort Massac white band; these white bands may be ex- State Park, Fox Lake, Fox Ridge State Park, tremely narrow on all the segments but are Frankfort, Franklinville, Fulton, George Field always conspicuous on the posterior tarsal ( usPHs), Gilman, Glencoe, Golconda, Gor- segments and may occupy a quarter of the ham, Gossett, Grafton (usPHs), Grand Tower, length of each segment. Wings entirely Granite City ( usPHs), Grantsburg, Grass Lake, bluish-brown scaled. Grayslake, Grayville, Great Lakes Naval MALE.—In size and color similar to Training Station, Halfday, Hamel, Hardin, female, differing chiefly in the long palps, Harding, Havana, Hazel Crest, Hebron, Herod, Herrin, Homer, Horse Shoe Lake, which have a white-scaled band at the base Jerseyville, Joetta, Johnston City ( usPHs), of each segment. Genitalia, fig. 133, readily Joust, Kampsville, Kankakee, Kappa, Karnak, distinguished by the following characteris- Kcensburg, Keithsburg, La Grange, Lake tics: basistyle with only an inconspicuous Bluff, Lake Fork, Lai.e Glendale, Lake Villa, Jugust, 1947 Ross: MOSQUITOES OF ILLINOIS 69

La Rue, La Salle, Lawrenceville (useHs), Lib- fig. 119; lateral portions of tergites each ertyville, Lincoln, Mahomet, Makanda, with a patch of white scales contrasting Marissa, Mascoutah, Mattoon, Mazon, Mc- noticeably with the tawny scales; venter Henry, Metropolis, Mill Shoals, Mississippi with a mixture of white and tawny scales. Palisades State Park, Momence, Monticello, Legs, fig. 130, for the most part with a salt- Morris, Mount Carmel, Mount Vernon, Mount Zion, Muncie, Neoga, New Boston, New and-pepper mottling of tawny scales and Haven, New Holland, Northmoor, Oak Park, black scales; tarsi definitely banded with Oakwood, Oilfield, Olney, Oregon, Orland the apical portion black scaled, the basal Park, Oswego, Palatine, Palestine, Palos Park, portion white scaled. Hind tarsi with apical Patton, Pecatonica, Pembroke, Peoria ( usexs), segment almost entirely white scaled, sec- Pere Marquette State Park, Pike, Pingree ond, third, and fourth segments each with a Grove, Pittsfield, Princeton, Quincy, Ravinia, basal band of white scales that cover a third Reynoldsville, Richmond, Ridge Lake, Rising to a half of the segment; basal segment Sun, River Forest, Robinson, Rockford, Rock with a basal band of white scales and a cen- Island (useus), Rockton, Rosecrans, Rossville, Round Lake, Roxana, Russellville, St. Charles, tral band of tawny scales, the latter about St. Jacob, St. Joseph, Salem, Sandoval, Savanna as long as half the segment. Wings with a ( uselis), Scott Field, ( useits), Seneca (useHs), mottled appearance, the scales along all the Seymour, Shawneetown, Skokie, Springfield, veins being a salt-and-pepper mixture of Starved Rock State Park, Sugar Grove, Sulli- dark scales and light scales. van, Thomson, Urbana, Utica, Venedy Sta- MALE.—Similar in general to female with tion, Vienna, Viola, Volo, Wadsworth, Walters- the following differences: beak without a burg, Ware, Watseka, Wauconda, Waukegan, the apical two-thirds being Wedron, West Vienna, Wetaug, White Heath, definite band, White Pines Forest State Park, Willow chiefly tawny scaled; palps very long and Springs, Winnetka, Wolf Lake, Woodstock, with distinct apical brushes, the basal seg- Yorkville, and Zion. ment being mostly tawny scaled. Male genitalia, fig. 138, of a very simple type. Basi- style nearly parallel sided, with a slight indi- Subgenus Taeniorhynchus ArribAlzaga cation of a basal lobe, bearing at this point 4. Aedes sollicitans ( Walker) a cluster of hairs. Claspettes of moderate length, with a long apical blade curved at LARVA.—Fig. 98. Head fairly wide, with apex. short, tufted preantennal hairs and usually This species was recorded from Illinois single (rarely double) upper and lower by Chandler (1920) and by Matheson hairs, the lower hairs almost directly ante- (1930), and has since been taken at a few rior to upper ones and without intervening Each occurrence has tufts. Eighth segment with comb forming scattered localities. an irregular scattered triangle, composed been associated with salt water from mine of about 14 to 20 small scales. Air tube or oil well drainage. In two instances, at short and robust, two to two and one-half Dupo and at Central City, the species times as long as wide; hair tuft multiple occurred in tremendous numbers. The branched, situated beyond pecten, and of severe and persistent biting led in each case moderate length; pecten forming a close to the organization of local control meas- and even series of about 20 teeth, the apical ures. In the Dupo area the salinity of water two or three usually more widely separated in which breeding occurred was three times than the others. Anal segment completely the average for ocean water. ringed with sclerotized plate; anal gills very Like vexans, this species is an intermit- short, budlike. tent breeder. The eggs, which are laid in FENIALE.—Length of wing 4.5 mm. Beak dry places, hatch at subsequent floodings, black, with a wide white band near middle, and there are new outbreaks of adults fol- palps black tipped with white, dorsum of lowing most summer rains. The larvae head golden. lUesonotum predominantly develop very rapidly after hatching, and a golden-brown scaled, the lateral areas and wave of adults follows in quick succession. sometimes a mesal stripe darker brown. Illinois Records.—Many larvae, collected March 18 to October 27, and adults, collected Pleurae with many white scales. Abdomen April 29 to October 14-, are from Benton, with tawny scales forming a fenestrated pat- Cahokia (usrfts), Carterville (usems), Central tern made up of narrow basal bands and a City, Centralia, Chanute Field ( useFfs), Crab wider mesal band of tawny scales against Orchard Lake (usrxs), Dupo, Granite City a blue-black background, very similar to ( uses-is), Herrin, Johnston City ( useus), Law- 70 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. I renceville ( usPHs), Mount Vernon ( usPHs), gills slender and pointed, slightly longer Savanna ( usPHs), Scott Field ( usPHs), West than anal segment (after Dyar). Frankfort, White City ( usrns), and White FEMALE.—Similar in size and almost all Heath ( usPHs). particulars of color and structure to the female of sollicitans, differing chiefly as fol- 5. Aedes nigromaculis (Ludlow) lows: hind basitarsus having no center band of tawny scales, being black scaled with a LARVA.—Head similar to that of sollici- basal band of white scales; tibiae predomi- tans, having upper and lower head hairs nantly black with a conspicuous scattering single. Eighth segment with comb forming of white scales on the anterior face; wings an irregular scattered triangle composed of entirely dark scaled. 14 to 20 scales. Air tube short and robust, MALE.—Genitalia, fig. 136, very similar two to two and one-half times as long as in most particulars to those of sollicitans, wide ; hair tuft beyond pecten multiple differing chiefly in the round and projecting branched and short; pecten occupying most basal lobe. The setae on this lobe are longer of the length of the tube with several con- than in sollicitans. spicuously detached teeth at the apex. Anal This species is primarily southeastern in segment completely encircled by sclerotized distribution. Our only record for Illinois ring. Anal gills twice as long as anal seg- is a single female collected on the south side ment, pointed, representing the chief differ- of Chicago, May 18, 1906, by Charles A. ence between this species and sollicitans. Hill; it was recorded as Aeries taeniorhyn- ADULTS.—In length and color almost rhus ( Wiedemann) by Gerhard in 1910. identical with those of sollicitans, differing The lack of subsequent records indicates in the coloration of the abdomen, in which strongly that it represents an adventive. The the dorsal, mesal, and lateral bands of pale specimen probably came north by train. scales are all practically pure white. The width of the white band on the beak and the Subgenus Aedes ( Meigen) central band of pale scales on the hind basitarsus both vary considerably, sometimes 7. Aedes cinereus Meigen represented by only a few pale scales. No LARVA.—Fig. 101. Head wide and rela- characters have yet been found to separate tively short; upper and lower hairs each with satisfactorily the male genitalia of sollici- four to seven filaments, the lower hair tans and nigromaculis. almost directly laterad of the upper hair A western species, nigromaculis has so far and only slightly anterior to it; no accessory been taken only once in Illinois. A single tuft between or in front of upper and lower female was caught in the light trap at the pairs. Eighth segment with comb forming Savanna Ordnance Depot, July 7, 1945, and an irregular line or an irregular triangle of collected by S. Mittler. This record was 10 to 15 large well-separated teeth. Air first discovered by Captain Charles F. Ger- tube moderately elongate, about four and lach, U. S. Public Health Service, to whom one-half to five times as long as wide; hair I am greatly indebted for information re- tuft short, usually quadruple, situated be- garding it. yond pecten; pecten with about 14 teeth, the No larvae of this species have yet been basal ones very small, the apical ones very taken in the state. The species frequents long and widely separated. Anal segment saline pools throughout the great plains with the tergite encompassing only about area and westward. one-half the segment; anal gills slender and sharp, about as long as the air tube. 6. Aedes mitchellae ( Dyar) FEMALE.—Length of wing 4 mm. Head, including beak and palps, dark brown to LARVA.—Head similar to that of sollici- black. Mesonotum entirely reddish-brown tans. Eighth segment with comb more com- scaled with a few postero-lateral and pos- pact than in sollicitans. Air tube somewhat tero-mesal areas of grayish scales. Abdo- slender, more than three times as long as men with dorsum almost entirely bluish- wide ; hair tuft usually seven branched, sit- black scaled, the base of each segment with uated beyond pecten; pecten composed of a a narrow crescent of cream scales at the close row of small teeth. Anal segment base; venter of abdomen almost entirely completely ringed by sclerotic shield; anal white or cream scaled. Legs with tibiae and August, 19-17 Ross: MOSO LI MES OF ILLINOIS 71 tarsi entirely bluish-black scaled, the femora five times as long as wide; pecten with one with the anterior faces usually dark, the to three apical teeth detached, ventral tuft posterior faces whitish. Wings entirely situated beyond the pecten and very long. dark scaled. Lateral comb consisting of an irregular MALE.—In size and general color simi- patch of about 25 scales. Anal segment lar to female. Palps represented by short with dorsal shield covering little more than stubs, very similar to those of the female one-half the segment, the anal gills about as and entirely unlike those of any other Illi- long as the segment, narrow and tapering. nois species of the genus. Abdomen with FEMALE.—Length of wing 6 mm. In basal white bands more pronounced than in color and general characteristics, this spe- the female. Male genitalia, fig. 135, differ- cies is very similar to stimulans, differing as ing from all others in the genus by the fol- follows: mesonotum usually with much lowing distinctive characters: dististyle in- more extensive reddish-brown areas and serted some distance from the apex of the meso-epimeron without bristles. basistyle; dististyle with prominent sclero- MALF.—In color and general structure tized processes at base and having apex similar to male of stimu/ans. Genitalia, fig. divided into a Y-shaped fork; basistyle with 155; similar in general proportions to those a pointed, projecting apex, a broad base of stimulans but differing markedly as fol- bearing a sharp basal lobe, and also a lows: ventral aspect of basistyle seeming to branched sclerotized mesal lobe; claspettes have basal lobe projecting as a triangular entirely lacking. area; in reality the basal lobe is a large and This mosquito, which is crepuscular and somewhat rectangular area folded back a ready biter in the vicinity of its larval against the mesa' face, covered with rows habitat, is common in the many small water of short fine setae and without any indica- holes that abound in the glacial bogs and tion of a macrochaeta. marshes in the northeastern corner of the To date we have found this species in only state. Apparently it produces annually only the northeastern corner of the state, where one generation, which emerges in late May it inhabits the spring pools in some of the or early June. marshes and bogs. It appears to favor zledes rinereus was formerly known under marsh situations that border woods and is the name of fuscus Osten Sacken, and a found usually in company with stimulans specimen was so recorded from Glen Ellyn, and fitchii. It has only a single generation Illinois, May 30, 1908, by Gerhard (1910). per year, and its habits are very similar to In addition to many records of the species those of stimulans. We have never found from northeastern Illinois, we have scat- it in Illinois in the tremendous numbers that tered records from other parts of the state, characterize colonies of stimulans. :Mathe- especially the southern fourth. The records son (1930) recorded the species from sev- from southern Illinois were associated with eral localities in northeastern Illinois. In (but not reared from) woodland pools. addition, he gave a record from Urbana, Illinois Records.—Antioch, Cahokia (usPHs), which is in the central part of the state; Cairo (usPHs), Camp Grant (usrns), Carter- this specimen, however, appears more like ville (uspns), Crab Orchard Lake (usms), fitchii, although it is in very poor condition Chemung, Elgin, Glencoe, Gorham, Great and does not provide a good basis for a defi- Lakes Naval Training Station, Kankakee, nite record. Keithsburg, Lawrenceville (usPHs), Pingree iledes excrucians is Holarctic in distribu- Grove, Ravinia, Roxana, Scott Field (usPits), In North America it is restricted to Skokie, Springfield (usPHs), Vol°, Wauconda, tion. Waukegan, and Zion. the northern coniferous forest belt and areas a short distance southward. Our Illinois records appear to be on the southern limit Subgenus Ochlerotatus ArribAlzaga of its range in this longitude. 8. Aedes excrucians Walker Illinois Records.—BpcH: June 10, 1933, Mohr & Townsend, 1 9. ELK GROVE: May LARVA.—Fig. 103. Length 10 mm. Head 2-6, 1942, 113, 21 9, 6 larvae, VoLo: April wide. Lower head hairs usually double, 24, 1942, Ross & Burks, April 29, 1942, Ross & upper head hairs usually triple, but fre- Samuels, 12 larvae; May 4-5, 1942, Ross & quently double, and any of the four occa- Burks, 1 9 , 5 larvae. WADSWORTH: June 3, sionally single. No accessory hairs or tufts 1943, Ross & Sanderson, 83 ; June 10, 19+2, between them. Air tube elongate, about Ross & Sanderson, 173, 1 9. WAUCONDA : 72 ILLINOIS NATURAL HISTORY SURVEY BULLETIN (A. 24, Art. 1

April 21, 1942, Ross & Riegel, 1 larva ; April pond, Ross & Sanderson, 1 8'. KANKAKEE: Aug. 29, 1942, 3 8. 4, 1938, Burks & Boesel, 1 9 . WOODSTOCK : June 4, 1943, cattail marsh, Ross & Sanderson, 1 8. Ziox: June 19, 1941, 1 9. Aedes flavescens Muller 9 ; June 10, 1942, Mohr & Burks, 1 9 . LARVA.—Head wide, upper and lower hairs multiple, the upper ones sometimes 10. A edes stimulans Walker double. Eighth segment with comb forming a triangular patch of scales. Air tube LARVA.—Fig. 104. Length 9 mm. Head over three times as long as wide, the pecten wide, lower head hairs usually single, rarely reaching the middle, with the last two teeth double, upper head hairs usually double but detached. Anal segment with dorsal plate occasionally single, triple, or quadruple. covering only the dorsal half of the segment. Eighth segment with lateral comb forming Anal gills as long as the anal segment and a rough triangle of about 30 scales. Air tapering to a point. tube about three and one-half times as long FEMALE.—Length of wing 7 mm. Head as wide; pecten composed of an even series, and mesonotum golden brown with areas the ventral tuft situated beyond it, usually shading to a more yellowish cast. Beak and three haired, and longer than width of seg- palps black with white scales scattered ment at base of tuft. Dorsal shield covering along the entire length. Dorsum of abdo- little more than half of segment; gills pointed men entirely cream scaled. Legs, except and usually slightly shorter than segment. for the tarsi, mostly cream scaled. Basi- FEMALE.—Length of wing 6 mm. Beak tarsus a mixture of white and black scales, and palps with a mixture of brown scales the apical tarsal segments with the basal and white scales. Mesonotum varying from halves entirely white scaled, the apical halves grayish brown to reddish brown, with gray- dark scaled. Wings almost entirely cream scaled stripes or areas along the lateral half scaled with a few black scales mixed in and always nearly covering the scutellum. with them. Mesopleurae with a group of three to six MALE.—In size and general color similar epimeral bristles. Dorsum of abdomen to female, palps with an apical brush. Gen- mostly dark scaled, each segment with a italia, fig. 152, as follows: apical lobe large basal band of white scales, the bands small and projecting; basal lobe large and tri- and crescentic on the basal segments, becom- angular, with many short setae and a single ing wider and more extensive toward the large conspicuous macrochaeta; claspette apex. Hind tarsi with basal segments having a short stout base with fairly long mostly white scaled; second, third, and apical filament, and beyond this a long nar- fourth dark scaled with a basal white band row neck and enlarged apical head which occupying about a third of the segment. tapers to a narrow tip. Wings mottled with brown scales and white To date we have taken only isolated scales, the dark ones predominating. adults of this species from the state, all from MALE.—Sinnlar to female in color and the northeastern portion, from near the structure. Palps with apical brushes. White Wisconsin border to Kankakee, some 100 bands on abdomen usually much more exten- miles farther south. The males we took sive. Male genitalia, fig. 153: basistyle with in the vicinity of marshes in which the larvae well-developed apical lobe; basal lobe devel- probably breed. oped as a large mesal lobe bearing many Our records for this species, which is short setae and a large macrochaeta, but Holarctic in distribution, are on the south- projecting only slightly as seen from ventral ern edge of its range. The Illinois records view; claspette curved and narrow, its apical given by Matheson (1930) for this species filament elongate with a long slender base, from Algonquin prove to be for fitchii„ but a sharp upper projection near middle, and our present records from Franklinville and from this point gradually tapering to a slen- Woodstock are close to Algonquin. The der curved tip. species is believed to have only one genera- Three Aides species, stinzulans, excru- tion per year and the adults seldom are clans, and fitchii, form a group the females abundant enough to be a nuisance. of which are frequently difficult to identify. Illinois Records.—Awriocx: May 21, 1941, The characters given in the key are not 1 , 1 9 . FRANKLINVILLE: June 4, 1943, marsh infallible, but will serve to separate most August, 1947 Ross: MOSQUITOES OF ILLINOIS 73 specimens. Characters of larvae and of ulans with the following diagnostic features: male genitalia offer very satisfactory means head gray, mesonotum with the mesal third of diagnosis. bright reddish brown, the lateral third hoary Aedes stimulant occurs in tremendous gray with a few reddish-brown scaled areas, numbers in and near woodland pools and scutellum gray; meso-epimeron usually with stump holes in the northeastern corner of only two bristles. Illinois. The larvae, which appear shortly MALE.—In size and general color similar after the annual spring thaw, develop slowly, to female. Genitalia, fig. 154: basistyle with but are usually full grown by the time the projecting rod, apical lobe bearing a scat- first warm weather of late May occurs. tering of long setae projecting mesad; basal The adults soon emerge, and during June lobe large and bearing a dense cluster of and early July many woods in the vicinity very fine long setae, in addition to the basal of northeastern Illinois are teeming with macrochaeta. Claspette with basal portion ferocious biters. The species has only one nearly straight, the apical filament short and generation per year. Outside of the north- curved, bladelike, and with its underside eastern corner of the state, we have records notched at the extreme base. of isolated colonies as far south as the cen- Both Gerhard (1910) and Matheson tral portion of the state. Early records of (1930) recorded this species from Illinois. about 1906 and 1910 indicate that this spe- Most of our recent records for it are from cies may have been much more abundant the northeastern corner of the state. Here in central Illinois during the early part of the species breeds in abundance in practically the century, before so many extensive tracts every open marsh. It is usually found asso- of upland timber were cleared. ciated with Culiseta inornata or Aedes ex- The range of stimulans is widespread cracians, but in some marshes it occurs as a throughout the northeastern states, across pure colony. Our only records south of the north central states, through Canada, northern Illinois were obtained by Hart and into the Yukon. Illinois is on the south- from Urbana in 1887 and from Havana in ern limit of its range. 1892. We have a recent record taken from Illinois Records.—Larvae, collected April Savanna, which is in the extreme northwest- 15 to April 25, and adults, collected April 28 ern part of the state. The species has to July 20, are from Algonquin, Antioch, Ben- apparently only one generation per year. senville, Bishop, Camp Grant (usPHs), Elk Our Illinois records appear to be on the Grove, Glencoe, Gurnee, Halfday, Highwood, southern limit of the range of this species, Momence, Muncie, Northmoor, Palatine, Princeton, Ravinia, River Forest, Rockford, which has a wide northern distribution simi- Rock Island, Rondout, Rosecrans, Starved lar to that of stimulant. Rock State Park, Urbana, Utica, Vol°, Wads- Illinois Records.—Larvae, collected April worth, Waukegan, Yorkville, and Zion. 29 to June 10, and adults, collected May 3 to October 5, are from Algonquin, Antioch, Elk Grove, Franklin (Cook County), Franklin- 11. Aedes fitchii Felt & Young ville, Glencoe, Great Lakes Naval Training Station, Halfday, Lake Bluff, Orland Park, LARVA.—Fig. 109. Length 9 mm. Head Palos Park, Ravinia, River Forest, Sand Lake, wide, lower hairs usually double, occasion- Savanna, Urbana, Volo, Wadsworth, Wauke- ally single or triple, upper hairs usually gan, Willow Springs, Woodstock, and Zion. triple, occasionally double, and rarely quadruple. Lateral comb somewhat triangular, 12. Aedes thibaulti Dyar & Knab composed of about 25 scales. Air tube elongate, about five times as long as its width LARVA.—Head, fig. 97, wider than long; near middle of pecten, tapering markedly preantennal and both upper and lower head and gradually from base to apex ; pecten hairs long, the lower head hairs usually consisting of 20 to 25 scales forming an even quadruple, the others with five or more row; ventral tuft situated just beyond pee- branches; clypeal hairs very wide apart, ten and very long. Anal segment with dor- three-quarters as far apart as distance be- sal shield covering nearly two-thirds of seg- tween upper head hairs; lower head hairs ment; anal gills longer than segment and considerably laterad of and only slightly pointed. anterior to upper hairs; antennae very long, — FEMALE. Length of wing 6 mm. Color over three-quarters as long as head, antennal and general structure in general as for stim- tuft very long. Eighth segment with comb 74 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1

consisting of a trianguloid patch of scales. 13. Aedes grossbecki Dyar & Knab Air tube about four and one-half times as long as wide, with pecten consisting of about LARVA.—Fig. 113. Length 10 mm. Head 20 scales arranged in an even row, ventral wide, lower hairs usually double or triple, tuft situated just beyond pecten, usually six upper hairs usually triple, sometimes dou- branched, the branches longer than the ble or quadruple. Lateral comb of segment greatest width of the tube. Anal segment 8 forming a triangular patch consisting of with dorsal shield longer than wide, cover- about 30 scales. Air tube three and one- ing about two-thirds of the segment; anal half times as long as wide, tapering only gills about as long as segment, tapering to slightly; pecten teeth forming an even row ; a blunt tip. ventral tuft situated just beyond pecten and FEMALE.—Length of wing 4 mm. Beak as long as, or slightly longer than, width of and palps black, head gray. Mesonotum, air tube at base of tuft. Anal segment with fig. 122, with a bluish-black mesal patch that dorsal shield covering about one-half of is narrow on the anterior half of the meso- segment; anal gills about as long as seg- notum but that on the posterior half occu- ment and tapering. pies nearly the entire width of the segment. FEMALE.—Length of wing 5 mm. Beak Antero-lateral areas of the mesonotum are and palps black, with scattered white scales, a bright gray, with scales long and slender each palp with a small tuft of white scales and not forming a shingled patch; abdomen at apex; dorsum of head covered with gray bluish black with small white lateral patches and white scales. Mesonotum with an at the bases of most of the segments; legs irregular pattern, fig. 118, the lateral area with tibiae and tarsi entirely black, femora white scaled, the mesal third of the anterior with anterior and apical portions black, with half bright brown scaled and the major por- conspicuous white knee rings and white tion of the disc of the posterior half black basal areas; wings entirely brownish-black scaled, the posterior border white scaled ; scaled. these areas are variable and merge one into MALE.—Similar in size and color to another. Dorsum of abdomen irregularly female ; palps very long and with apical scaled, the ground pattern dark scaled with brushes. Male genitalia, fig. 139, with a scattering of white scales, and each seg- broad basistyle that has a prominent apical ment with an arcuate basal area of white and basal lobe and peculiar claspettes; the scales. Legs, fig. 124, mostly white scaled, claspette blade is contorted into a somewhat the middle and posterior pair with irregular irregular hook-shaped structure unlike that areas of black scales; hind tarsi banded, of any other North American species in the segments 2 to 5 with basal third to half genus. Otherwise, the species shows a white scaled, apex black scaled, basitarsus marked affinity to trivittatus, on the basis mostly white scaled but not definitely banded. of the small but definite apical and basal Wings with a mixture of white scales and lobes of the basistyle. black scales. All the wing scales are very Published records indicate that this species wide, fig. 169, a characteristic that sets off is primarily a south central species and has this species from all other Illinois members been found in abundance in Arkansas. The of the genus. Illinois records represent the most northern MAI.E.—In size, color, and wing scaling locality in which the species has been taken. similar to female. Palps with large apical An excellent account of its life history is brushes. Male genitalia, fig. 157: basistyle given by Horsf all (1940). It usually breeds with projecting apical lobe bearing several in holes within the bases of standing trees. rows of hairs curved dorsad; basal lobe It seems to prefer swamp situations and, wide and steplike, the macrochaeta some- according to some writers, shows a marked what isolated on the ventral edge, the re- preference for the bases of sweet gum and mainder with a cluster of long setae; clasp- tupelo gum trees. ettes with base curved, apical filament with Illinois Records.—CAI OKIA: June 29, 194-3, a slender base and an expanded apex that Snow, 1 S ( usPHs). CARTERVILLE : June 27, tapers to a curved sharp tip. (usrus) ; May 31, 1944, 1 ( uspHs). 19+2, 1 y Although not abundant, this species is MARION: June 2, 1942, Johnson, 1 j ( usPHs). common throughout the post oak flats along SCIFT FIELD: J one 25, 191-2, 29 ( usPHs) ; June 16, 194-3, 29 ( usPHs) ; June 18, 1943, 19 the Mississippi River in extreme southern ( usPHs). Illinois. Outside this area only isolated

August, 1947 Ross: MOSQUITOES OF ILLINOIS 75

specimens have been taken, but these extend the known range in the state north as far as Chicago. The only Chicago record is that of Gerhard (1910), who recorded a male from Chicago and a female from Palos Park under the name A edes sylvicola Grossbeck (now considered a synonym of grossbecki). The adults of grossbecki emerge early in the spring and apparently have only one generation per year. Outside of Illinois the species has been recorded from only a few localities to the South. We have encountered the adults in the field so rarely that we know little of their habits. Illinois Records.—Several larvae, collected April 3, and adults, collected April 6 to June 17, are from Cache, Crab Orchard Lake, Gor- ham, Grand Tower, La Rue, Mount Vernon, Reynoldsville, St. Jacob, Urbana, and Ware. Fig. I68.—Portion of wing of 21 edcs stimulans. 14. A edes trivittatus Coquillett

LARVA.—Fig. 108. Head fairly wide, upper and lower head hairs always long and single; preantennal hair short and eight- branched ; accessory hairs absent. Eighth segment with a triangular comb consisting of short pointed scales. Air tube fairly short and robust, about two and one-half times as long as wide; hair tuft fairly short and six to eight branched, situated beyond apex of pecten; pecten consisting of about 15 fairly long teeth arranged in an almost per- fectly regular row. Anal segment completely ringed by sclerotic plate; anal gills long and tapering, frequently twice length of anal segment. FEMALE.—Length of wing 5 mm. Beak and palps black, dorsum of head white scaled. Mesonotum, fig. 115, with a long dark central wedge, flanked on the side by a wide stripe of white scales; the anterior Fig. 169.—Port: on of wing of Aedes gross- portion of the mesonotum has a dark stripe bccki. Note the wide scales on the veins com- laterad of the light stripe. Dorsum of abdo- pared with those of fig. 168. men almost entirely dark scaled with small lateral triangles of white scales on the apical segments; venter almost entirely white scaled with black lateral triangles on basal segments. Femora pale scaled with stripes of black scales on apical areas; tibiae and tarsi dark scaled with narrow lines of whitish scales on the ventral edge; wings entirely dark scaled. MAI.E.—In size and color similar to Fig. 170.—.4edes triseriatus, scales on pro- female. Male genitalia, fig. 151: basistyle natal lobe, lateral aspect. with apical lobe only moderately developed, Fig. 171.—.4edes thibaulti, scales on pro- shoulderlike; basal lobe steplike, with a notal lobe, lateral aspect. 76 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1 very sinuate macrochaeta and many long head, the tuft distinctly beyond middle of slender setae. Claspette curved, its apical antennae and the apical portion markedly filament with a definite neck and head, the more slender than the basal portion. Upper back of the head produced into one to sev- and lower head hairs usually double, occa- eral spinelike barbs, the tip slender and sionally one of them triple, each lower head slightly hooked. hair at least twice as far laterad as it is The male of this species is very similar in anteriad of upper head hair. Eighth seg- many respects to that of infirmatus Dyar & ment with comb varying from an irregular Knab. In infirmatus, fig. 150, the macro- single or double row of about 10 scales to chaeta of the basal lobe has a definite thick- an irregular patch of about 20 scales. Air ened angle near the base, the basal lobe tube nearly four times as long as greatest itself is diagonal to the main axis of the width; pecten with 12 to 20 scales, the basistyle, and the basistyle is more slender. basal ones very short and broad, the apical The claspettes of the two species are very 2 or 3 detached from the remainder ; ventral similar. tufts multiple and markedly longer than edes trivittatus is one of the extremely greatest width of tube. Anal segment not annoying species encountered in Illinois. It completely ringed by sclerp'si:ed plate, hut is a fierce biter, even in the day time, and with a ventral membranous strip about as occurs in a wide variety of temporary pool wide as in fig. 110B. Gills tapering and of situations. The adult emergence apparently moderate length. occurs principally during the late spring, FEMALE.—Length of wing 4 mm. Beak generally later than that of sticti-us and and palps black, head varied with golden canadensis and frequently coinciding with and dark brown. Mesonotum, fig. 123, that of vexans. The larvae have been found having a large central purplish-black area in shady woodland pools usually resulting with narrow lateral areas of gray scales from spring rains or spring floods. In our shading to gold where the lateral and mesal recent collecting, the adults have been en- areas meet, scutellum with a small gray countered in great numbers many times, but area flanked on each side with a short and the larvae have been taken very seldom and very narrow golden line. Dorsum of abdo- only in small numbers. men almost entirely bluish black, the lateral In Illinois this species is distributed fairly portion of each tergite having a white patch uniformly over the entire state. Its range just visible from dorsal view. Legs with covers the northeastern and north central tibiae and tarsi almost entirely blue black, states with a few records extending into the some of the scales gray; femora with apical southern states. and dorsal portions black, extreme apex of Illinois Records.—Larvae, collected May 8 each with a small white knee spot, basal to September 17, and many males and females, portion cream. Wings entirely bluish-black collected May 4 to November 29, are from scaled. Antioch, Baker, Cahokia (usPHs), Camp Grant MALE.—In size, color, and general struc- (u.se .$), Carterville (usrHs), Champaign, Chicago, Crab Orchard Lake (uspHs), Dan- ture similar to female. Palps with a large ville, Des Plaines, East Peoria (usPHs), East apical brush. Male genitalia, fig. 141: basi- St. Louis, Edwardsville, Glencoe, Great Lakes style moderately narrow with a large tuft Naval Training Station, Halfday, Havana, of long conspicuous setae at apex ; apical Herod, Homer, Joetta, Kappa, Keithsburg, lobe set off as a shoulder, its dorsal margin Lake Fork, Mascoutah, Matanzas Lake, with an irregular linear area of setae curv- Moinenc, Muncie, Neoga, New Boston, Oak- ing dorsad; basal lobe represented by a wood, Pere Marquette State Park, Princeton, detached sclerotized plate on the mesal face Ravinia, St. Jacob, Savanna (usPHs), Scott of the basistyle, this sclerite with a scatter- Field (usPHs), Seneca (usPHs), Seymour, ing of short setae and a single large dorsal Spring.:eld, Starved Rock State Park, Syca- more, Urbana, Utica, Wadsworth, Ware, macrochaeta arising from the dorsal mar- Weldon Springs, and Zion. gin; claspette with a short curved base, the apical blade long, bearing a large barb on 15. Aedes aurifer Coquillett its upper surface and tapering to a slender curved apex. LARVA.—Fig. 100. Head wider than long, The male genitalia of this species are of clypeal bristles moderately far apart. Anten- the same type as those of intrudens Dyar, fig. nae very long, nearly as long as length of 142. The two differ somewhat in details August, 1947 Ross: MOSQUITOES OF ILLINOIS 77 of the claspette and apical tuft of the basi- and round, with one short and one long style, but more particularly in the basal macrochaeta and with many slender setae; lobe. In intrutlens the basal lobe bears these setae are very short near the macro- three macrochaetae, one at the extreme chaetae and increase in size to the dorsal base and two on the dorsal margin. margins of the lobe, fig. 145B; claspettes The range of aurifer extends throughout with slender bases, the apical filament of the northeastern and north central states. each angled near middle and tapering to a We have only a single record of the species slender tip. for Illinois, a female taken in the vicinity This species is similar in general appear- of a cypress swamp at Karnak, May 15, ance to Aeries campestris Dyar & Knab. 1941, by Mohr & Burks. This specimen The males, however, differ markedly in the was collected considerably south of other setation of the basal lobe. In cam pestris, aurifer records in the western portion of fig. 146, this lobe bears long setae of almost the range of the species. The distinctive equal length over the entire surface and has color markings of this specimen check per- only a single macrochaeta, which is little fectly with the markings of specimens from larger or longer than the other setae. The Michigan and Rhode Island. females are practically impossible to identify; in the past it has been considered that in 16. Aedes dorsalis Meigen dorsalis the third vein (R4,5) was almost entirely dark scaled whereas in cam pestris LARVA.—Head fairly wide; upper and this vein was largely white scaled. Reared lower head hairs long, always single, the series from individual colonies have shown lower hairs almost directly anterior to the that this differentiation does not hold, since upper ones and without intervening tufts. both extremes and various intermediate Eighth segment with comb triangular, com- conditions occur in dorsalis alone. posed of small sharp scales. Air tube mod- The first Illinois reports of dorsalis were erately stout, two and one-half to three from the suburbs of Chicago and were re- times as long as wide, hair tuft about six corded by Gerhard (1910) using the name branched, situated beyond pecten; pecten Aedes curriei Coquillett, a name then in use with about 20 teeth forming an evenly spaced for this species but since that time sunk as row. Anal segment with sclerotic shield a synonym of the Holarctic dorsalis. The covering only dorsal half of segment; anal species was reported from Oak Park, Illi- gills very short and budlike. nois, by Matheson (1930) as Aedes dor- FEMALE.—Length of wing 4.5 min. Most salis. At the same time Matheson recorded of body and appendages cream to tawny four females of dedes campestris from Riv- scaled; beak tawny brown; mesonotum erdale, near Chicago, Illinois. There seems tawny; usually with a narrow brown mesal no doubt that these Riverdale specimens are stripe and another brown stripe along each true dorsalis and not cam pestris, because all lateral margin, fig. 119, sometimes with males taken in the Chicago area have proved additional narrow brown stripes and some- to be dorsalis, and these specimens come well times without any brown stripes; abdomen within the range of variation of reared cream scaled, the basal segments usually series from nearby localities. each with a pair of lateral spots of dark Only a few colonies of dorsalis have been scales. Legs mostly cream scaled with a found in the state, and all have been associ- mixture of black scales, especially toward ated with waters contaminated by industrial the apexes of the femora; tarsi mostly black wastes. In southern Illinois, one colony scaled with a white fringe at the base and occurred with sollicitans in saline water from apex of each segment. Wings cream scaled, oil wells, and in northern Illinois other col- usually but not always with an irregular onies were in the seepage areas from several mixture of black scales on most of the veins. factories. The species is an irregular, inter- MALE.—In color similar to female except mittent breeder, and usually a brood of that the brown stripes on the mesonotum adults emerges following each inundation by are usually darker and wider. The palps rain of the affected areas. have apical brushes as in canadensis. Geni- The adult females are fierce biters and talia, fig. 145, as follows: basistyle with appear to be predominantly crepuscular. apical lobe only moderately developed and Illinois Records.—Larvae, collected April square shouldered; basal lobe projecting 22 to May 9, aud adults, collected April 9 to 78 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, /frt.!

October 10, are from Cahokia (us0Hs), Camp the season; the adults emerge in April and Grant (usPHs), Chanute Field (usPns), Dupo, May. The species frequents chiefly wood- East Moline, East St. Louis, Great Lakes Naval land pools, especially those flooded by seep- Training Station, Oak Park, Riverdale, age water in the spring independent of high Savanna (usms), Scott Field (usPHs), and water in the streams. In southern Illinois, Summit. it occurs primarily in the post oak flats along the Mississippi. In other parts of the 17. Aedes canadensis Theobald state it is found in stump holes, small sink holes, and isolated oxbows oÆ small wood- LARVA.—Fig. 105. Head wide; upper land streams. In rare instances it is found and lower hairs multiple, five to eight in practically unshaded situations. branched, similar in length and fanlike The females are fierce biters and attack appearance to preantennal hairs. Eighth readily in shaded situations through most segment with comb somewhat triangular, of the day. They live for many months, composed of a large number of small scales. and, in woodland situations, isolated speci- Air tube moderately slender, nearly four mens are encountered well into the sum- times as long as wide; hair tuft long, usu- mer. To date the species has not been in- ally five branched; pecten forming an even criminated as a carrier of disease. row of about 15 teeth, the apical teeth Illinois Records.—Larvae, collected March slightly wider apart than the others. Anal 18 to May 23, and many males and females, segment with sclerotic shield covering only collected April 11 to August 1, are from Alpha, the dorsal half of the segment; anal gills Altamont, Antioch, Bensenville, Benton, tapering and pointed, about as long as the Cache, Camp Grant (usms), Carbondale, Car- terville (1;s0lis), Casey, Centralia (usms), segment. Cottage Grove, Crab Orchard Lake (usms), FEMALE.—Length of wing 4 mm. Beak Danville, :)arwin, Des Plaines, Effingham, and palps brown, the latter with a minute Elgin, Elk Grove, Equality, Giant City State tuft of white scales at extreme tip. Meso- Park, Glencoe, Golconda, Gorham, Grand notum uniformly golden brown and with a Tower, Grantsburg, Grimsby, Halfday, Her- few indistinct gray lines along lateral mar- od, Ina, Johnston City (usms), Jonesboro, gins and on or near scutellum. Dorsum of Kankakee, Karnak, La Rue, Marion, Mascou- abdomen dark scaled with an almost uni- tah, Momence, Mount Vernon, Muncie, Oak- wood, Raven, Ravinia, Reynoldsville, Rond- form narrow band of white scales at has out, St. Jacob, Salem, Scott Field (us0us), of each segment. Tarsi each with a fairly Springfield, Starved Rock State Park, wide band of white scales at both base and Urbana, Utica, Vienna, Volo, Wadsworth, apex, tibiae almost entirely dark scaled, Waltersburg, Ware, Waterloo, Wauconda, femora mostly white scaled with dorsal West Vienna, Willow Springs, Yorkville, portions dark scaled. Wings uniformly and Zion. bluish-brown scaled. MALE.—Similar in size, color, and gen- 18. Aedes sticticus (Meigen) eral characters to female, differing chiefly in the long palps, each of which extends be- LARVA.----Fig. 107. Length 8 mm. Head yond the beak and has a large apical brush with upper and lower hairs of only moder- embracing the last two segments and the ate length, usually two to four branched but apex of the preceding segment. The white occasionally with an odd hair single, the bands on the dorsum of the abdomen are exact combination of branching extremely much wider than in the female. Genitalia, variable and frequently asymmetrical; lower fig. 140: basistyle with large ovate apical head hairs almost directly anterior to upper lobes bearing a dense cushion of flattened hairs. Eighth segment with comb triangu- wide setae, basal lobes wide and triangular, lar, composed of small scares. Air tube with a uniform brush of very slender setae fairly short, about two and one-half times and a larger single macrochaeta at base; dis- as long as wide; hair tuft short, usually six tistyle elongate, with an apical seta; clasp- branched; pecten with 15 to 20 teeth ar- ette moderately long and stout, with a slen- ranged in a close, evenly spaced row. Anal der sinuate filament. segment with sclerotic plate covering about This species, which is one of the most three-fourths of segment; anal gills taper- widespread in the state, has only one genera- ing and pointed, about as long as anal seg- tion per year. The larvae mature early in ment. August, 1947 Ross: MOSQUITOES OF ILLINOIS 79

FEMALE.—Length of wing 4 mm. Beak during the evening and also during the day and palps black, the beak with a small group in cloudy or shaded situations. Emergence of gray scales at apex; dorsum of head gray of the adults occurs once a year, in early scaled. Mesonotum, fig. 116, with a broad spring. The larvae seem to require shaded mesal brown band extending from anterior pools for development. margin to scutellum and divided down the Illinois Records.—Larvae, collected April 3 meson by a very narrow line of gray scales; to August 18, and many males and females, ber 25, are from Alto lateral bands of mesonotum and scutellar collected April 6 to Octo Pass, Belleville (usmis), Billett, Bishop, Cache, region gray; supplemental short brown Cahokia (usPHs), Cairo, Calvin, Camp Grant bands are usually present on the posterior (usmis), Carbondale, Carterville (usrns), half of the lateral areas, these bands always Casey, Caseyville, Charleston, Clinton, Crab short and separated from the mesal band by Orchard Lake (usrus), East St. Louis, Ed- at least a definite line of gray scales. Dor- wardsville, Fox Ridge State Park, Fulton, sum of abdomen definitely banded, the apical George Field (usPHs), Glencoe, Golconda, two-thirds of most of the segments dark Gorham, Grafton (usPHs), Grand Tower, scaled, the basal third white scaled. Femora, Granite City (usPirs), Grantsburg, Grayville fig. 125, mostly white scaled, the dorsal edge (usmis), Great Lakes Naval Training Station, Halfday, Havana, Herod, Homer, Hurst, and apical portion of each black scaled; Inman, Joetta, Johnston City (usPHs), Kan- tibiae usually with upper and lower mar- kakee, Kappa, Karnak, Keensburg, Keiths- gins black scaled, sides predominantly pale burg, Lake Fork, La Rue, Lawrenceville scaled; tarsi predominantly black scaled, (usrus), Mascoutah, Matanzas Bay, Mo- without banding, the posterior basitarsus rnence, Mount Carmel, Mount Vernon, (usPHs), with white scales often extending as irregu- New Boston, New Haven, Oakwood, Pales- lar lines from base to near apex. Wings tine, Palisades, Patton, Pere Marquette State predominantly black scaled, the costal and Park, Pike, Pingree Grove, Prophetstown, subcostal areas frequently with many white Pulaski, Ravinia, Reynoldsville, Ridge Lake, Rising Sun, Rockford, Russellville, St. Jacob, scales mixed with the black ones. Savanna (usPHs), Scott Field (usmis), Shaw- MALE.—Size and general color as for neetown, Springfield (usmts), Starved Rock female. Genitalia, fig. 148; basistyle with State Park, Tamaroa, Urbana, Utica, Ware, very large projecting apical lobe, which West Vincennes, Willow Springs, Wolf Lake, bears along its mesal edge a series of setae and Zion. curved dorsad; basal lobe forming a triangular flap markedly detached from basi- 19. Aedes sPenceril (Theobald) style and connected with it chiefly by membranous folds, with a macrochaeta at ex- LARVA.—Length 8 mm. Head wide, both treme base, and with the apical portion upper and lower head hairs almost always curved and bearing fairly stout setae. Clasp- single but occasionally one of them double. ettes slender, with a short apical filament Terminal segments very similar to those of that is expanded near base. rexans, fig. 102. Air tube scarcely more Holarctic in range, this species in N orth than two and one-half times as long as wide; America is widely distributed from coast to pecten with apical two or three teeth mark- coast. In much of the recent literature it edly detached; ventral tuft short and be- has been called hirsuteron (Theobald) in yond pecten. Lateral comb consisting of the East and aldrichi Dyar & Knab in the about 10 to 12 scales, ;trranged in a regular West. Dr. Alan Stone writes me that he single or double row. Anal segment, fig. believes these two are the same species and 110B, almost completely ringed by dorsal should be considered under the name sticti- plate, with only a narrow, V-shaped area of cus. Edwards (1932) has synonyn-dzed membrane between the ventral edges of the altlrichi with lateralis ( Meigen). Dr. Stone plate, bearing one or two ventral hair tufts writes that there is some doubt as to the anterior to apical mesal barred areas; gills identity of intern/is and believes it prudent tapering, longer than segment. to use sticticus for the species. FEMALE.—Length of wing 5 mm. Color In Illinois sticticus is extremely common of beak, head, mesonotum, and legs similar along the flood plains of the larger rivers, to color of corresponding parts of sticticus. where it breeds in flood pools. At times Each segment of dorsum of abdomen, fig. individuals of the species appear in great 117, with a median stripe of white scales, swarms, and the females are ferocious biters an apical band of white scales, and a nar- 80 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art.1 row basal band of white scales, the center of ovate, detached from basistyle, connected the lateral area being dark scaled. In very with it chiefly by membranous folds and by light specimens the dorsum of the abdomen a short sclerotized bridge on which arises may be almost entirely white scaled. Wings the macrochaeta. Claspette slender, its api- predominantly dark scaled but with many cal filament curved and saber shaped. of the anterior veins mostly pale scaled, We have only one record of the species especially toward the base. from Illinois, a series of four females from MALE.—Similar in general to the female Ware, August 14, 1942, Ross & Mohr. The but with the abdomen darker; in dark ex- specimens were collected as pupae from a tremes the first four segments may be almost temporary rain pool in the post oak flats entirely dark scaled. Male genitalia, fig. along the Mississippi River. The species is 149, similar in general to those of sticticus, predominantly southern and southeastern with the following differences: apical lobe in distribution, and the Illinois record is the of basistyle more diagonal and longer; apical one farthest north. filament of claspette with a small but pronounced notch at the base of the apical fila- 21. Aedes fulvus pal/ens E. S. Ross ment. We have only a single Illinois record of LARVA.—Fig. 95. Head wide; upper this species, from Savanna, June 19, 1942, head hairs long and single, lower ones long in light trap (usPHs). The species is re- and double, situated as far anterior to the ported to be widespread and abundant in upper ones as half the distance between the the Great Plains region. The larvae have upper hairs; between the lower hairs are a been taken in temporary rain pools and pair of very fine, branched hairs; preanten- marshes in Minnesota (Owen 1937). nal hairs short and multiple. Thorax unique among the Illinois species in having the three 20. Aedes duPreei (Coquillett) lateral meso-thoracic tufts each 15 to 20 branched and relatively stout. Eighth seg- LARVA.—Fig. 111. Head wide, with ment with comb triangular, composed of upper and lower hairs long, the upper hairs about 30 small scales. Air tube short and usually single, the lower ones double and sit- tapering, stout, only twice as long as wide ; uated almost directly anterior to upper ones; ventral tuft large with about 14 filaments, the species is unique in having the latero- situated ventrad of the pecten and consider- dorsal hair of the frons branched. Eighth ably before its apex; pecten consisting of segment with a comb consisting of an even about 15 teeth, of which the 1 to 3 apical row of about six long teeth. Air tube only teeth are long, large, and well separated, relatively long but narrow and tapering at the remainder small and forming a close apex, nearly four times as long as wide; hair row. Anal segment completely ringed with tuft long, about six branched, situated before sclerotized dorsal shield; anal gills long middle of siphon but beyond end of pecten; and tapering, nearly twice as long as air pecten consisting of an even row of few tube. large teeth. Anal segment completely ringed FEMALE.—Length of wing 5.5 mm. Integ- by sclerotic shield; anal gills extremely long, ument of almost entire body bright golden over twice length of air tube, each gill con- yellow except for a dark brown rectangle taining a distinct trachea. at each postero-lateral corner of the meso- FEMALE.—Length of wing 2.5 mm. Beak notum, irregular dark brown areas at the and palps black, dorsum of head white ends of the abdominal tergites, and the scaled. Mesonotum with a wide silver stripe almost black antennae. Body with conspicu- extending its entire length, the lateral area ous long slender hairs. Beak and palps yel- dark brown, abdomen entirely dark scaled. low scaled, the extreme apex of both tipped Legs almost entirely black scaled, except for with black scales. Mesonotum with scales the inner faces of the front and middle of the ground color, very thin and scarcely femora and all but the apexes of the hind wider than short setae. Abdomen with dor- femora. Wings entirely dark scaled. sum predominantly yellow scaled, the apex MALE.—Size and color as for female. of each segment with a band of black scales. Male genitalia, fig. 147: basistyle with pro- Legs yellow scaled, the knees and apical tar- jecting and sharp apical lobe that bears only sal segments black scaled. Wings predomi- isolated short setae; basal lobe somewhat nantly yellow scaled. August, 1947 Ross: MOSQUITOES OF ILLINOIS 81

MALE.—Similar in size and color to of moderate length, slightly more than three female. Genitalia, fig. 143: basistyle with times as long as wide; lateral tuft very long projecting and pointed apical lobe that con- and stout, usually with four filaments; pec- tinues basad to beyond the middle of the ten short, with about 15 teeth that usually hasistyle and ends in a low but definite form an even row in which the apical ones shoulder; basal lobe completely detached become slightly more separated. In some from basistyle and joined to it by membra- cases the apical one or two teeth may be defi- nous folds, its macrochaeta appearing as a nitely detached from the row. Anal seg- part of the basistyle proper rather than a ment completely circled by its sclerite; anal part of the basal lobe; macrochaeta very gills moderately long, tapering, and sharp. long, flattened, widened at apex, and arising FENTALE.—Length of wing 5 mm. Beak from a straplike internal thickening of the and palps black scaled. Dorsum of head integument; basal lobe with slender setae. and mesonotum tawny or golden scaled, the Claspette with base slender, its apical fila- mesonotum frequently with a wide mesal ment beyond the short neck abruptly en- band of reddish-brown scales. Abdomen larged to form a wide blade. with dorsum dark scaled, each segment with Our Illinois specimens belong to the sub- a basal band of white scales, the bands nar- species pallens. It and its relatives have row at the base of the abdomen and becom- been treated in considerable detail by E. S. ing progressively larger toward apex. Legs Ross (1943). with femora mostly pale scaled, tibiae pale We have only two records for this spe- with a mixture of dark scales, the tarsi pre- cies from Illinois, both from the southern dominantly dark scaled, without banding. quarter of the state (Ware and Mount MALE.—Similar in size and color to Carmel). In addition, there is in the Chi- female. Palps with a large apical brush. cago Natural History Museum a specimen Genitalia, fig. 158: basistyle with a large from Hessville, Indiana, which is only a few ovate apical lobe, clothed with a cluster of miles from Chicago. This last specimen, fairly short setae, all pointing dorsad; basal which is a female, may have been carried to lobe with ventral aspect forming a definite Hessville from Illinois or states farther shelflike projection, the setae abundant and south by rail or other transportation. The confined primarily to mesal aspect, macro- Mount Carmel specimen, a male collected chaeta single and moderately inconspicuous. in 1906, would seem to indicate that at least Claspette with curved base, its filament nar- one colony existed in southern Illinois at row and angled, thickest at the angle. that time. The Ware record consisted of Formerly known under the name abser- four larvae collected August 14, 1942, Ross ratus Felt & Young, this species occurs in & Mohr, from a rain pool in the post oak great numbers in a tamarack bog near Volo flats; two of the larvae were reared, and and in lesser numbers in neighboring bogs males emerged. The species is primarily in the northeastern corner of the state. The southeastern, and the Illinois records are larvae live in the sphagnum mat of shaded apparently on the northwestern edge of its pools. In the bog at Volo such pools occur range. in the tamarack and poison sumac belt a few The female from Hessville, Indiana, was paces back from the open edge of the bog recorded by Gerhard (1910) as Aedes bimac- and contain no other mosquitoes except ulatus (Coquillett), and the male from occasional colonies of cinereus. Mount Carmel, collected June 30, 1906, Our Illinois records for inzplacabilis was recorded by Matheson (1930) as Aedes appear to be on the southern limit of the cataphylla Dyar. range of the species, which is northeastern in distribution. Only a single generation 22. Aedes implacabilis ( Walker) of adults emerges each year, in the late spring. The females are apparently crepus- LARVA.—Fig. 106. Head relatively wide; cular and do not bite to any considerable upper and lower hairs very long, usually extent during daylight hours, even on days single, sometimes double, the lower hairs that are cloudy. almost directly anterior to the upper hairs Illinois Records.—ANnocH: May 21, 1941, and without accessory hairs between them. 2 ; April 23-30, 1942, 2 3 , 19. Vow: April Eighth segment with comb consisting of an 23, 1942, many larvae ; April 26, 1942, 7 8, arcuate row of five to seven teeth. Air tube 2 ; May 3, 1942, 1 8 ; May 13, 1942, Ross,

82 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Voi. 24, Art.

Burks, & Mohr, 11 specimens, 1 ; May 16, The group is essentially southern. The 1942, many ,8 and 9. WAUCONDA : emerged range of the eight species known from Illi- April 27, 1942, 1 8 . nois does not extend far north of this state. Three other species of the genus occur 23. Aede.s- punctor (Kirby) within the territorial limits of the United States: pygrnaea (Theobald) is recorded LARVA.—Head with the upper and lower from southern Florida; signipennis ( Coquil- hairs usually double. Eighth segment, air lett) and /ongipa/pis Roth occur in the cen- tube, and anal segment similar to those of tral plains states and southwestward. The implarabilis, differing chiefly in the comb. larvae are treated by Pratt (1946). This has about 12 teeth forming a long irreg- The species of this genus form three very ular row (from Dyar). distinct groups, which have been considered ADULTS—In size and general color indis- as subgenera. It is interesting to note that tinguishable from i mplarabilis adults. Male the female genitalia of all the Illinois spe- genitalia, fig. 156, differing in the following cies are practically identical. characters: apical lobe with longer and more abundant setae, which are curved dor- KEY TO SPECIES sad ; basal lobe much more massive, the LARVAE sclerotized portion of the basistyle not ex- 1. Head quadrate, antennae short, slender, tending out onto the lobe, the lobe curved and without definite tufts, fig. 174; and bearing abundant short setae over its large predaceous larvae 2 entire surface and a very conspicuous mac- Head oval, antennae long, stout, and with rochaeta at its basal corner; claspette with definite tufts, fig. 173; small to fairly apical appendage short, curved, and nar- large, bottom feeders 3 2. rowed at tip. Lateral hair of anal segment with two to four branches, separating at base of hair The only Illinois record of this species is 1. ciliata a single male collected as a pupa in a tama- Lateral hair of anal segment single, or rack bog pool at Volo; the adult emerged forked some distance from base April 26, 1942. This specimen was col- 2. howardii lected in a large colony of inzp/arabi/is. 3. Antennae very large and inflated, air Examination of hundreds of mosquito larvae tube small, fig. 172 8. discolor and males from the locality failed to dis- Antennae not inflated and air tube large close a second specimen of punctor. The and swollen, fig. 173 4 4. Upper and lower head hairs multiple.... habits and distribution of punctor are almost 7. confinnis identical with those of iniplacabilis. Upper head hairs single or double, lower head hairs single to triple 5 10. PSOROPHOR A S. Upper and lower head hairs single • Robineau-Desvoidy 3. cyanescens Upper and lower head hairs double or The females of this genus are fierce bit- triple. .4. ferox; 6. varipes; 5. horrida ers and the adults in many of the species are diurnal or nearly diurnal in habit. The FEMALES life history of the genus is very similar to 1. Wing length over 6.5 mm., usually 7 to 8 that of Aeries. The eggs are laid in damp mm.; mesonotum having a narrow mesal ground cover and do not hatch until flooded. band of scales, flanked by a linear bare polished band on each side, fig. 26; The larvae mature very rapidly. Larvae of hind femora each with a prominent two species are predaceous and feed on other tuft at apex, fig. 28 2 mosquito larvae; larvae of other members of Wing length under 5 mm., usually 3.5 to the genus are vegetarian and in the field 4.5 mm.; mesonotum with entire area are easily confused with those of Aetles. All scaled ; hind femora sometimes bushy, species of the group breed intermittently fig. 30, but not with well-marked tufts throughout the summer. The larvae fre- 3 2. Mesonotum quent temporary rain pools or flooded areas with mesal band of scales yellow, hind tibiae and tarsi very bushy of many types. The adults of one or more 1. ciliata species may appear in clouds soon after sum- Mesonotum with mesal band of scales mer rains. All species hibernate in the egg black, hind tibiae and tarsi pubescent stage. but not unusually bushy....2. howardii ugust, 1947 Ross : MOSQUITOES OF ILLINOIS 83

Figs. 172-174.—Psorophora larvae: 2/, apex of abdomen, lateral aspect; B, dorsum of head. Mouth brushes are omitted from head drawings. 84 ILLINots NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. I

COMB SCALE AIR TUBE

PECTEN TOOTH

Fig. 175.—Psorophora horrida, larval parts. (After Roth.)

COMB SCALE

PECTEN TOOTH

Fig. 176.—Psorophora longipalpis, larval parts. (After Roth.) August, 1947 Ross: MOSQUITOES OF ILLINOIS 85

3. Hind tibiae and tarsi entirely purple; Each tarsal segment entirely dark or en- abdominal tergites purple, but with api- tirely light; a leg may be banded but cal yellowish bands that are slightly with an alternation of entirely dark broken on the meson ....3. cyanescens and entirely light segments; rarely one Hind tarsi either with all segments banded segment may be banded 6 with white or with one or more segments 5. Wings mostly dark scaled but with a all white, or dorsum of abdomen with only small lateral white spots, as in fig. fairly even speckling of white scales; 120 4 hind basitarsus nearly black, with two 4. Each tarsal segment with apex dark and bright white bands, a narrow one at base with a white band, as in fig. 28 .. extreme base and a wider one at mid- 5 dle of segment 7. confinnis

Fig. 177 .—Psorophora ciliata, male genitalia. (After Matheson.) Fig. 178.—Psorophora howardii, male genitalia. (After Matheson.)

86 ILLINOIS NATURAL HISTORY SURVEY BULLETIN I' rd. 24, Art. /

Wings with white scales grouped into defi- Hind tarsi having last two or two and nite lines or patches on some veins; one-half segments white, the remainder hind basitarsus mostly white scaled but black 5. horrida with dark scales intermingled uniformly along its entire length MALES 8. discolor 1. Dististyle with a large mesal lobe and a 6. Mesonotum golden scaled over its entire long mesal spurlike projection, fig. 178 area 4. ferox 2. howardii Mcsonotum with mesal half black scaled, )ististyle without mesal processes 2 lateral fourths white scaled, forming 2. Dislistyle with tip truncate and apical longitudinal bands 7 spur situated before apex, fig. 180 7. Hind tarsi having next to last segment 6. varipes white, the remainder black Dististyle with tip tapered and small, 6. varipes apical spur situated at end, fig. 179...3

Fig. 179.--Psorophora yanescens, male genitalia. (After Matheson.) 180.—Psorophora s'.. ar;pes, male genitalia. ( After Matheson.) Fig. 181.—Psorophora confinnis, male genitalia. (After Matheson.) Fig. 182.—Psorophora discolor, male genitalia. (After Matheson.) .,4ugust, 1947 Ross: MOSQUITOES OF ILLINOIS 87

3. Dististyle narrow and sinoate, with a teeth; tibiae and tarsi purple except mesal row of bristles and a sharp sub- for a few segments of hind tarsi, which apical ventral tooth, fig. 177...1. ciliata may be white Janthinosoma Dististyle expanded near middle, without Palps of male upturned ; claws of female niesal row of bristles and without ven- without subapical teeth; tibiae with tral tooth, fig. 181 4- numerous white scales, tarsi having each 4. Apex of claspettes with a series of simple segment banded with white at base, setae and two flattened contorted leaflets (lark at apex Grahhamia at lateral corner, fig. 183: 1 4. ferox ; 5. horrida Subgenus PsoroPhora Apex of claspettes without contorted leaf- Robineau-Desvoidy lets, at most with scales and thickened hairs, figs. 179, 182 5 This subgenus includes two species, ciliata 5. Apex of claspettes with a dense series of and howardii. hairs and scales, fig. 179..3. cyanescens Apex of claspettes with a series of only four to eight long, thickened hairs, fig. 1. Psorophora ciliata (Fabricius) 131 6 6, Apex of claspettes with four or five thick- LARVA.—Fig. 174. Head quadrate, with ened hairs, fig. 182 8. discolor short slender antennae and only a few incon- Apex of claspettes with five to eight thick- spicuous hairs. Eighth segment with the ened hairs, fig. 181 7. confinnis comb consisting of an arc of scales arranged along the edge of a slightly sclerotized cres- SYNOPSIS Or SUBGENERA REPRESENTED I N ILLINOIS cent. Air tube long and moderately robust, tapering to apex, with pecten consisting of 1. Adults with mesonotum having a pair of longitudinal, pale shining areas on each scales that are sclerotized at base and hair- side of a narrow mesal band of scales; like at apex. Anal gills very long. large species, gallinippers. Larvae pre- FEMALE.—Length of wing 7 to 8 mm. daceous, having quadrangular heads and Body integument yellowish brown, with the small antennae without tufts, fig. 174.. central part of the mesonotum dark brown Psorophora to almost black; pubescense of many areas Adults with mesonotum having a uniform not sufficiently dense to obscure the integu- covering of scales; small to moderate mental color. Beak and palps with erect, size species. Larvae vegetarian, with ovate heads and long, tuft-bearing an- shaggy, dark or tawny scales, dorsum of tennae, fig. 173 2 head covered with white scales. Mesono- 2. Palps of male not upturned at end; tarsal tum, fig. 26, with a narrow center stripe of claws of female with large subapical white scales, flanked on each side with a pol-

Fig. 183.—Psorophora, male genitalia. 1, P. horrida; 2. P. longipalpis. ( After Roth.) 88 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Pol. 24, Art.1

ri'iata larvae, which breed in rain pools, usually with large numbers of A edes vexans and with other species of Psorophora, move bout among the other larvae and cause no commotion. When hungry, a ciliata larva imply makes a grab with its mouthparts and mouthbrushes for one of the smaller 9T larvae (it seldom misses) and gradually maneuvers it so that, with the head or tail in its mouth, it can swallow its victim whole. In actions and habits in securing prey, ciliata larvae are almost the exact counterparts of the gars among the fish. Usually a full grown ciliata larva will consume three or four other larvae per day. In spite of their large size, ciliata larvae mature as rapidly as the smaller species. The ciliata females are vicious biters. After a blood meal, they are almost a terri- fying sight, due to their large size and busi- ness-like appearance. They attack on cloudy days as well as during the evenings. The larvae, which breed in a wide variety of rain pools, are not frequently encountered, but in this state are generally associated with edes vexans. Fig. 184.—Psorophora ciliata, female geni- Widely distributed from Central America talia. A, dorsal aspect; B, ventral aspect; C, lateral aspect. Abbreviations: r, cercus; p, through the central and eastern states to postgenital plate ; s, sternite ; t, tergite. southeastern Canada, the species occurs generally over Illinois. It was recorded from Chicago by Gerhard (1910) and from ished pale stripe. Laterad of this is a nar- Urbana by Matheson (1930). row stripe of hairs and black scales and Illinois Records.—Larvae, collected May 25 laterad of this is a large area clothed with to September 8, and many males and females, white scales. Abdomen chiefly tawny or collected May 29 to October 21, are from white scaled. Apical fifth of femora and all Algonquin, Beach, Beardstown, Bement, Bishop, hind tibiae and tarsi very shaggy, with erect Bridgewater, Cahokia (usPHs), Camp Grant black scales; extreme base of each hind (USPHS), Carbondale (usPris), Carterville tibia and basal fourth or fifth of each tarsal (usPlis), Cave-in-Rock, Champaign, Chebanse, Chicago, Crab Orchard Lake (usPHs), Downs, segment with a band of appressed white East St. Louis, Fountain Bluff, Gorham, Graf- scales. Front and middle tibiae and tarsi ton (usPHs), Grand Tower, Granite City yellow, not shaggy. Wings dark scaled and (usPuts), Great Lakes Naval Training Station, usually inconspicuous. Havana, Homer Park, Marion (usPHs), New MALE.—Similar in size, color, and general Holland, Newton, Oregon, Pingree Grove, structure to female. Palps very long, much Rockford, Savanna (usPHs), Scott Field longer than beak, the apical three segments (usPHs), Thompson's Lake, Urbana, Ware, with a very large, extensive shaggy brush. West Vienna, and Zion. Male genitalia, fig. 177: dististyle sinuate and narrow, bearing a mesal brush of bristles 2. Psorophora howardii Coquillett and a dorsal triangular projection near apex; claspettes long, free from basistyle, LARVA.—Almost identical with that of the apex of each with a row of thickened cilia/a. The only reliable difference found hairs and with a flattened sinuate leaflet on to date is the single or split condition of the lateral corner. lateral hair of the anal segment (this hair This species is of unusual interest because is branched from base in cilia/a). it is one of the few whose larvae are preda- FEMALE.—Similar to ciliata female in size, ceous on other mosquito larvae. The big general color, and characteristics. It differs August, 1947 Ross: MOSQUITOES OF ILLINOIS 89 chiefly in having the mesal stripe of the sclerotized area. Air tube swollen, about mesonotum composed of black scales, and three times as long as wide; pecten with in having the hind tibiae and tarsi yellow three or four teeth. Anal gills slender, very and only moderately spiny ; identical to cili- long and pointed. ata female in appearance of the front and FEMALE.—Length of wing 4.5 mm. Beak middle legs. and palps black or purplish. Integument MALE.—Similar to female in size and of head and thorax dull black. Dorsum of color. Palps very long, the apical brush head and entire mesonotum covered with represented by short scattered hairs. Geni- whitish scales. .Dorsum of abdomen with talia, fig. 178, of striking appearance; clasp- segments purple scaled except for an apical ette ending in an ovate hairy lobe; dististyle band of white scales, the band of the apical with a large, long flaplike mesal projection, segments interrupted on the meson. Legs the inner apical corner prolonged into a long with femora almost entirely yellow; ex- slender beak. treme apexes of femora and all the tibiae This species has a wide distribution that and tarsi purple; extreme tips of femora embraces the Neotropical region and most each with a small whitish knee spot. Legs of the southern part of the United States. purple scaled, the scales inconspicuous. It has been taken several times in southern MALE.—Genitalia as in fig. 179: dististyle Illinois and occasionally in central Illinois. sinuate, expanded at middle; claspettes free The records for this state apparently repre- from basistyle only near apex; apical mar- sent the northern limit of the species gin of claspettes with a dense row of hair range. The larvae have been reared from and scales and with a long curved spine pools in woodlands and from pools in ruts on the lateral corner. through a pasture. In the latter case they Adults of this species have been taken in occurred together with Psorophora ciliata numbers in southern Illinois but to date we and Aedes vexans. In southern Illinois they have found no larvae. The adults are very were taken, in company with vexans and P. unusual in many of their habits. They ferns, in woodland pools in the post oak attack during the day and seem to prefer flats of the Mississippi River valley. The bright sunlight. Extremely rapid fliers, species has never been found abundantly they make a high-pitched sound somewhat in the state. resembling that of a humming bird. They Illinois Records.—Larvae, collected June 9 are wary and circle a prospective victim 26 to to August 14, and adults, collected May before alighting. 'We found it necessary to 16, are from Cahokia (usims), Car- September let them get a good start at biting before terville (usrlis), Chanute Field (usims), Crab we could bottle them with certainty. On Orchard Lake (usrms), Goreville, Gorham, Grand Tower, New Athens, Scott Field one occasion Dr. Carl 0. Mohr and I en- (usrms), Springfield, and Ware. countered a flight of adults at West Vienna. When we stepped into the bright sun, the cyanescens females attacked quite readily. Subgenus Janthinosorna Arribalzaga When we retired into nearby shade, we were not molested. We repeated this action sev- The species of this subgenus are conspicu- eral times and always with the same results. ous by the purple iridescent areas on the A single female of this species makes so abdomen and legs, and the purplish cast on much noise that it can be heard approaching many parts of the body, such as the palps for several yards. and wing scales. As in other members of the genus, the Females of all the species in the sub- larvae are reported to breed in rain pools genus are vicious biters. of various types. Like howardii, this species extends its 3. Psorophora cyanescens ( Coquillett) range from the Neotropical region into the southern and central states. It has been LARVA.—(From Matheson 1944.) Head recorded from states as far north as Okla- oval, upper and lower head hairs single and homa, Kansas, and Illinois. long, antennae stout and cylindrical, each Illinois Records.—Adults, collected Iviay 21 with two- or three-haired tuft near middle. to September 15, are from Carterville (usPrrs), Eighth segment with lateral comb consist- Crab Orchard Lake (usPris), East St. Louis, ing of three or four stout scales on a small French Village (usims), Granite City (usPris), 90 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, "frt. I

Marion (usmis), New Holland, Savanna nois the species is encountered in much (usms), Scott Field (usPris), Ware, and West greater abundance in the southern half of Vienna. the state than northward. Illinois Records.—Larvae were collected at Karnak, April 29, 1941. Many males and 4. Psorophora ferox ( Humboldt) females, collected May 13 to October 14, are from Benson, Cahokia (usPlls), Carbondale LARvA.--Head ovate, antennae elongate, (usmisl, Carterville (usr0s), Champaign, with a multiple tuft near middle, upper and Crab Orchard Lake (usPHs), East St. Louis, lower head hairs double. Eighth segment Elsah, Fort Chartres State Park, Glencoe, Gorham, Gossett, Grand Tower, Grantsburg, with a comb of six or seven scales arranged Grayville, Havana, Herod, Homer, Karnak, along the edge of an indistinct sclerite. Air La Rue, Lawrenceville (usPlls), Mascoutah, tube stout, expanded, about three times as Momence, Oakwood, Patton, Quincy, St. Jacob, long as wide ; pecten of three or four Scott Field (usPns), Springfield, Urbana, stout teeth. Utica, Vienna, Ware, West Vienna, White FEMALE.—Length of wing 4.5 to 5.0 mm. Heath, and Wolf Lake. Integument of head yellowish brown, mesonotum almost black. Beak and palps cov- 5. Psorophora horrida ( Dyar & Knab) ered with purplish scales. Dorsum of head and pronotum with a uniform but not close LARVA—Fig. 175. Very similar to the covering of whitish or yellowish scales. larvae of ferox and varipes. To date, relia- Dorsum of abdomen purple with lateral ble and tested characters have not been found white spots visible on segments 4 to 7. to insure correct identification of the larvae Legs with femora yellow, the apical and of this group of species. upper areas purple; tibiae and tarsi purple FEMALE.—Length of wing 4.5 mm. Head except for the last two or two and one-half and thorax nearly black. Palps and beak segments of the hind tarsi, which are white; purple scaled. Dorsum of head white tip of femora with small white knee spots. scaled. Mesonotum with mesal third black Wings purplish-brown scaled. scaled, lateral third white scaled, these areas MALE.—Similar to female in size and forming definite longitudinal bands. Dorsum color. Palps elongate, with only a sparse of abdomen purple scaled with small white brush at apex. Male genitalia with disti- patches on some or all of the segments. style considerably expanded and leaflike, Femora with basal portions mostly yellow; claspettes with a long base, entirely free the apical and dorsal areas are black, and from basistyle, and with their apexes orna- the extreme tip (knee) is white; tibiae and mented with a row of setae and each having tarsi purple with the exception of the last two or three contorted leaflets on lateral two segments of the hind tarsi, which are corner; very similar to genitalia of horrida White. Wings purple scaled. (fig. 183:1). To date, no very satisfactory MALE.—Similar in size, color, and gen- characters have been found to separate the eral structure to female. Genitalia, fig. two species on genitalia. The color mark- 183:1, with dististyle swollen and leaflike; ings given in the key to females are much claspettes each with a long stalk, which is more trustworthy. free from basistyle, and with apex bearing Common in many parts of Illinois, this a row of setae and two contorted leaflets species is frequently a real pest. The at the lateral corner. females are fierce biters and attack readily A species of very similar coloration, longi- during the day in shady situations. The palpis Roth (1945a), is distinguished in larvae breed most abundantly in flood pools, lacking the white knee spot and also in de- and in stream or river valleys. The first tails of the male genitalia, fig. 183:2. The generation of adults emerges early in the larva of /ongipa/pis differs from that of hor- season, usually about the middle of May or rida chiefly in details of the chaetotaxy, fig. shortly afterward, and successive genera- 176. A species that occurs along the eastern tions are on the wing through the summer portion of the great plains, iongipa/pis may and well into September. eventually be found in Illinois. This species has a wide range from south- Very similar in habits and distribution to eastern Canada through the eastern United ferox, horrida breeds in immense numbers States into the Neotropical region. In Illi- in bottomland pools. It has been taken August, 1947 Ross: MOSQUITOES OF ILLINOIS 91 abundantly in the southern half of the state Subgenus Grahhatnia Theobald and less abundantly in the northern half. The females are vicious biters that attack The members of this group are non-metal- readily in the daytime. lic in color and drab in appearance. The Illinois Records.—Adults, collected May 4 scales of the occiput and mesonotum are to September 24, are from Camp Grant usually small and well separated. Another (usmis), East St. Louis, Elizabethtown, Fort characteristic of the subgenus is the mixture Chartres State Park, Grantsburg, IIavana, of white scales and dark scales on the wing; Joetta, Kappa, Karnak, La Rue, Mascoutah, in some species this mixture develops into Momence, Mounds, Mount Vernon (usmis), a definite pattern. Oak Park, Patton, Pere Marquette State Park, Quincy, Rockford, St. Jacob, Savanna, Scott Field (usmis), Seymour, Starved Rock State 7. Psorophora confinnis (Arribalzaga) Park, Urbana, Utica, Warsaw, Wedron, White Heath, White Pines Forest State Park, and LARYA.--Fig. 173. Head ovate, wider Whitesville. than long, with long antennae having a multiple tuft near middle; upper and lower head hairs multiple, usually with five or six 6. Psorophora varipes (Coquillett) branches. Eighth segment with comb consisting of about six scales arranged in a LARVA.—Practically identical with the crescent. Air tube slightly swollen near larvae of ferox and horrida. To date sat- . middle, tapering near apex ; pecten consist- isfactory characters have not been found to ing of about four teeth. Anal gills of mod- identify these forms. erate length, pointed. FEMALE.—Length of wing 4.5 mm. In- FEMALE.—Length of wing 4.5 mm. Palps tegument of head and thorax black. Beak dark-brown scaled with tip white scaled; and palps purple scaled. Dorsum of head beak with central half tawny scaled, base white scaled. Mesonotum with mesal half brown scaled and apex black scaled. Integ- black scaled, lateral fourth white scaled and ument of head and thorax sooty dark brown, forming a conspicuous stripe. Abdomen nearly black. Dorsum of head tawny scaled. purple with lateral white spots as in ferox. Mesonotum with a mixture of brown and Legs with base of femora yellow, apical and white scales. Dorsum of abdomen dark- dorsal portions purple ; tibiae and tarsi en- brown scaled with apical patches of white tirely purple with the exception of the scales; on segments 2 and 3, these form a fourth tarsal segment of the hind tarsi, which is white; apexes of femora each with continuous band across the segment and on a conspicuous knee spot. the segments beyond that they form a pair of lateral areas usually fairly well sepa- MALE.—Size, color, and general structure rated on the meson. Femora predominantly as for female. Male genitalia, fig. 180, with dark-brown scaled and having irregular dististyle expanded, broad to apex, apical white scales scattered throughout, with a spine situated just before the tip; claspettes definite band of white scales just before the long, free from basistyle, the apex with a apex, fig. 31, and with a prominent small row of spines and a foot-shaped leaflet on knee spot at apex ; tibiae dark-brown scaled lateral corner. with patches of white scales that make a This southern species has been taken only series of dots running down the full length in the southern third of Illinois. At times of the segment; tarsi of all legs nearly black, it is abundant in the cypress bottoms, and the the basitarsus with a very narrow white larvae probably breed in the summer rain ring at base and a definite tawny ring at pools of this area. It is a vicious biter and middle, the remaining segments with the is on the wing as early as the middle of May. basal third or half white. Wings with a No larvae have been taken in our recent fairly even mixture of white scales and dark survey; habits of the larvae are recorded as scales distributed so that no spots or bands being similar to those of other species in the result. genus. MALE.—Similar in size, color, and gen- Illinois Records.—Adults, collected April 30 eral structure to female. Palps long, the to August 15, are from Cache, Duck Pond Hill, Grand Tower, Grantsburg, Karnak, La Rue, apical two segments and part of the preced- Lawrenceville (usmis), Patton, Scott Field ing with a long, extensive, and conspicuous (usmis), and Ware. brush. Male genitalia, fig. 181: dististyle 92 ILLINOIS N ATURAL HISTORY SURVEY BULLETIN Vol. 24, Art. 1 expanded and leaflike in middle; claspettes very scales. Mesonotum with a mixture of each with short stem and solidly fused to brown scales and silvery gray scales, all of the basistyle; apexes of claspettes each with which are small and well separated, giving a row of five to eight thickened hairs. a stippled effect. Dorsum of abdomen pre- The larvae of this species breed in tempo- dominantly white scaled, with an irregular rary rain pools of pastures, farm yards, and mixture of brown scales, the scales normal other more or less open situations. The in size and overlapping. Femora with a females bite fiercely. mixture of white and brown scales, with a Breeding in immense numbers, this species definite preapical band of white scales, and is a scourge in the flooded rice fields of a white knee spot, the area between the Arkansas and other southern states. In Illi- preapical band and the knee spot predomi- nois it is common only in the southern part nantly brown; tibiae chiefly white scaled, of the state. It has been taken in small with an intermingling of brown scales, espe- numbers as far north as Chicago. Until, cially toward tips; basitarsus white scaled recently the name co!urnbiac was generally with brown scales predominant toward tip; used for this species, and under this name it remaining tarsal segments with basal half was recorded in Illinois by Matheson white scaled, apex brown to black. Wings (1930). The species is widely distributed predominantly white scaled, with an inter- from about the latitude of central Illinois mingling of brown scales that form a long south into the Neotropical region. irregular blotch near the middle of Costa Illinois Records.—Larvae, collected May 26 and many short lines scattered throughout to September 16, and many males and females, the rest of the wing, giving it an irregular collected May 27 to October 11, are from mottled appearance. Beardstown, Belleville (usrus), Benson, Ca- MALE.—Similar in size, color, and gen- hokia ( usots), Cairo ( usens), Carbondale eral structure to female. Palps very long, ( use:-is), Carterville ( ustms), Champaign, with an extensive conspicuous brush. Male Crab Orchard Lake (usmis), East St. Louis, genitalia, fig. 182, almost exactly as in Elizabethtown, French Village ( usmis), Graf- con finnis but usually with only four setae ton (usms), Granite City (usms), Grand Tower, Havana, Johnston City ( usnits), at the apex of each claspette. Marion (usPHs), Mount Vernon (usm-ls), Oak Adults of discolor have frequently been Park, Sandoval, Scott Field ( usnns), Spring- confused with those of signipennis (Coquil- Celt!, Vienna, Ware, and West Vienna. lett), a more western species. The signipennis adults may be distinguished by the barlike costal markings in the wings, which 8. Psorophora discolor ( Coquillett) are as definite as those in fig. 66. Occurring through most of the South, LARVA—Fig. 172. Head broad; anten- this species has been taken westward to nae very long, thickened, with a multiple Oklahoma and Texas. In Illinois it has dorsal tuft near middle and with two stout been taken chiefly in the southern fourth of spines on venter about two-thirds distance the state. It is recor4led as biting man, but from base; preantennal tuft double and long; in Illinois it is not numerous enough to be upper and lower head hairs single. Eighth a pest. The larvae breed in rain pools. segment with a crescentic comb of six scales The largest colony of larvae we encoun- united by a small sclerotized area. Air tcred in our Illinois survey was in a weed- tube very short, about as long as width of choked roadside ditch. The general area seventh segment, the tube itself about three was cleared and open, but the ditch was times as long as wide, with a pecten of about overgrown and heavily shaded with weeds. four or five long scales and with a multiple The larvae were wary and sparse, and some ventral tuft that is as long as the tube. patience was required to gather a series, Anal gills very long, with a trachea extend- one larva at a time. ing the full length of each. Illinois Records.—Larvae, collected June 8 FEMALE.—Length of wing 3.5 mm. In- to August 3, and adults, collected May 29 to September 27, are from Cahokia ( usPHs), Car- tegument of head and thorax dull, dark terville ( usmts), Crab Orchard Lake (usms), gray-brown. Beak with middle half pale East St. Louis, Fort Massac State Park, Graf- scaled, base and apex brown; palps brown ton ( usots), Granite City (usmis), IIerrin with a few white scales at tip. Head with a t usrns), Marion, Mount Carmel, Mount Ver- scattering of brown scales and narrow sil- non, Scott Field, Seneca (ItsPHs), and Ware. LITERATURE CITED Aitken, Thomas H. G. 1945. Studies on the anopheline complex of western America. Calif. Univ. Pubs. Ent. 7(11) :273-636. 39 figs. Bradley, G. H., and W. V. King 1941. Bionomics and ecology of Nearctic Anopheles. Am. Assn. Adv. Sci. Pub. 15: 79-87. Carpenter, Stanley J. 1941. The mosquitoes of Arkansas. Arkansas Board of Health, Little Rock, Ark. 87 pp., 15 pls. Carpenter, Stanley .I., Woodrow W. Middlekauff, and Roy W. Chamberlain 1946. The mosquitoes of the southern United States east of Oklahoma and Texas. Am. Midland Nat. Monograph 3. 292 pp., 155 figs. Chandler, S. C. 1920. A study of the malarial mosquitoes of southern Illinois. I. Operations of 1918 and 1919. Ill. Nat. Dist. Surv. Bul. 14(12) :307-28. 17 figs. II. Operations of 1920. Nat. Hist. Surv. Bul. 15(3 ) :23-32. 2 figs. Daggy, Richard R., Oswald J. Muegge, and William A. Riley 1941. A preliminary survey of the anopheline mosquito fauna of southeastern Minnesota and adjacent Wisconsin areas. Pub. Health Reps. 56(17) :883-95. Dickinson, W. E. 1944. The mosquitoes of Wisconsin. Milwaukee Pub, Mus, Bul. 8(3) :269-365, figs. 198- 230. Dyar, Harrison G. 1928. The mosquitoes of the Americas. Carnegie Inst. Wash. Pub. 387. 616 pp., 123 pls. Edwards, F. W. 1932. Diptera, Fam. Culicidae, in P. Wytsman, Genera insectorum, fasc. 194. Bruxelles: V. Verteneuil and L. Desmet. 258 pp., illus. Gerhard, W. J. 1910. A list of the mosquitoes in the vicinity of Chicago, Illinois. Ent. News 21:293-300. Gjullin, C. M. 1937. The female genitalia of Aecles mosquitoes of the Pacific Coast states. Ent. Soc. Wash. Proc. 39(9) :252-66. 20 figs. Horsfall, W. R. 1940. Biology of Thibault's mosquito. Ark. Ag. Exp. Sta. Ann. Rep. 51:66. Jenkins, Dale W., and Stanley J. Carpenter 1946. Ecology of the tree hole breeding mosquitoes of Nearctic North America. Ecol. Mono. 16(1) :31-48. 5 figs. King, W. V., and G. H. Bradley 1937. Notes on Culex erraticus and related species in the United States, Ent. Soc. Am. Ann. 30(2) :345-57. 1 pl., 1 fig. 1941. General morphology of Anopheles and classification of the Nearctic species. Dis- tribution of the Nearctic species of Anopheles. Am. Assn. Adv, Sci. Pub. 15:63-78. 6 figs., 1 pl. King, W. V., G. H. Bradley, and T. F. McNeel 1939. The mosquitoes of the southeastern states. U. S. Dept. Ag. Misc. Pub. 336. 91 pp., 26 figs. Matheson, Robert 1930. Distribution notes on Culicidae. Brooklyn Ent. Soc. Bul. 25(5) :291-4. 1944. Handbook of the mosquitoes of North America. The Comstock Publishing Co., Ithaca, N. Y. 314 pp., 33 pls. Owen, William B. 1937. The mosquitoes of Minnesota, with special reference to their biologies. Minn. Univ. Bul. 126. 75 pp., 11 figs. [93] 94 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 24, Art.

Pratt, Harry D. 1945. Mansonia indubitans Dyar and Shannon—a new mosquito addition to the United States fauna. Kans. Ent. Soc. Jour. 18(4) :121-9. 14 figs. 1946. The larva of Psoronhora (Janthinosoma) coffini Dvar and Knab and a key to the PsoroPtora larvae of the United States and the Greater Antilles ( Diptera, Culicidae). Ent. Soc. Wash. 48(8) :209-14. 1 fig. Pratt, Harry D., W. W. Wirth, and D. G. Denning 194-5. The occurrence of Culex opistbofius Romp in Puerto Rico and Florida, with a description of the larva. Ent. Soc. Wash. Proc. 47 (1): 24-5-9. 2 pls. Ross, Edward S. 1943. The identity of Aedes bimaculatus ( Coq.) and a new subspecies of Aedes fulvus ( Wied.) from the United States. Ent. Soc. Wash. Proc. 45(6) :143-51. 4 figs. Ross, Edward S., and H. Radelyffe Roberts 1943. Mosquito Atlas, Part I. American Entomological Society and the Academy of Natural Sciences of Philadelphia. iv + 44 pp. Roth, Louis M. 1943. A key to the Cu/ex ( Diptera, Culicidae) of the southeastern United States, by male terminalia. Kans. Ent. Soc. Jour. 16(4) :117-33. 1944. A key to the zinopke/es of the somheastern United States, by male genitalia ( Diptera, Culicidae). Am. Midland Nat. 31(1 ) :96-110. 1945a. The male and larva of Psorophora horrida ( Dyar & Knab) and a new species of Psorophora from the United States. Ent. Soc. Wash. Proc. 47(1) :1-23. 19 Cgs. 191-5b. Aberrations and variations in anopheline larvae of the southeastern United States. Ent. Soc. Wash. Proc. 47(9) :257-78. 66 Cgs. 1946. The female genitalia of the Wyeomyia of North America ( Diptera: Culicidae). Ent. Soc. Am. Ann. 39)2): 292-7. 1 pl. Rozeboom, L. E. 1942. The mosquitoes of Oklahoma. Okla. Ag. Exp. Sta. Tech. Bul. T-16. 56 pp., illus. Texas State Health Department 1944. The mosquitoes of Texas. Compiled by the Division of Medical Entomology, Bureau of Laboratories, Austin, Texas. 100 pp., 32 figs. Wirth, Willis W. 194-5. The occurrence of Cu/ex ( Melanoconion) elevator Dyar & Knab in Florida, with keys to the melanoconions of the United States. Ent. Soc. Wash. Proc. 47(7) :199- 210. 30 figs. I NDEX

The page entries in boldface type refer to the principal treatment of the families, genera, and species in the text. Names that are synonyms, or of changed generic assignment, are indicated by italic type.

A abserratus, Aedes, 81 Diptera, 1, 14 Aedes, 1, 2, 5, 6, 8, 9, 13, 16, 19, 20, 21, discolor, Psorophora, 9, 17, 82, 83, 86, 87, 92 22, 23, 24-, 40, 4-6, 51, 53, 54, 55, 56, 58, dorsalis, Aedes, 17, 57, 58, 61, 64, 77 60, 61, 62, 63, 65, 67, 70, 72, 82, dupreei, Aedes, 9, 17, 52, 56, 59, 62, 64, 80 Aedimorphus, 65, 68 aegypti, Aedes, 2, 4, 8, 9, 17, 23, 24, 37, 52, 56, 58, 59, 60, 65, 66, 67 alba, Orthopodomyia, 17, 36, 37 erraticus, Culex, 17, 23, 43, 44, 45, 47, 50, 51 aldrichi, Aedes, 79 Eucorethra, 16, 17 Anopheles, 1, 3, 5, 8, 14, 15, 17, 19, 22, 24, excrucians, Aedes, 8, 17, 54, 57, 59, 63, 64, 25, 26, 27, 28, 31, 51 71, 72, 73 Atiophelini, 17 apicalis, Culex, 6, 8, 17, 23, 41, 43, 44, 45, 46, 47, 51 atlanticus, Aedes, 61 fatigans, Culex, 49 atropalpus, Aedes, 67 ferox, Psorophora, 8, 17, 82, 86, 87, 89, 90, 91 aurifer, Aedes, 9, 17, 53, 57, 58, 59, 61, 64, Finlaya, 65 76, 77 Aedes, 6, 8, 17, 55, 57, 59, 63, 64, 71, 72, 73 fiavescens, Aedes, 8, 17, 57, 59, 62, 64, 67, 72 fulvus pallens, Aedes, 8, 17, 52, 53, 59, 61, barberi, Anopheles, 5, 7, 17, 25, 26, 27, 28 64, 67, 80 bimaculatus, Aedes, 81 fuscus, Aedes, 71

campestris, Aedes, 61, 77 Grabhamia, 87, 91 canadensis, Aedes, 6, 7, 8, 17, 20, 54, 57, 60, grossbecki, Aedes, 2, 6, 8, 9, 17, 56, 57, 58, 64, 67, 61, 76, 77, 78 59, 63, 64, 74, 75 cataphylla, Aedes, 81 Chaoborinae, 14, 16, 17 Chaoborus, 17 ciliata, Psorophora, 3, 8, 17, 20, 24, 82, 83, hirsuteron, Aedes, 79 85, 87, 88, 89, horrida, Psorophora, 17, 82, 84, 86, 87, 90, 91 cinctipes, Mochlonyx, 16 howardii, Psorophora, 9, 17, 21, 82, 85, 16, cinereus, Aedes, 8, 9, 17, 22, 53, 57, 59, 60, 87, 88, 89 65, 67, 70, 71, SI co/umbian, Psorophora, 92 confinnis, Psorophora, 17, 20, 21, 82, 83, 85, 86, 87, 91, 92 impatiens, Culiseta, 39, 40 consobrinus, Culiseta, 39 impatiens, Theobaldia, 39 Coquillettidia, 35 implacabilis, Aedes, 2, 6, 8, 17, 52, 55, 59, Corethrella, 17 63, 64, 81, 82 crucians, Anopheles, 9, 17, 26, 27, 31, 32 imlubitans, Mansonia, 35 Culex, 1, 3, 5, 8, 9, 13, 19, 21, 24, 28, 37, infirmatus, Aedes, 62, 76 40, 41, 42, 43, 44, 45, 46, 47 inhibitator, Culex, 51 Culicidae, 1, 14, 17 inornata, Culiseta, 5, 6, 8, 17, 21, 23, 24, 30, Culicinae, 14, 16, 17 37, 38, 39, 40, 73 Culicini, 17 intrudens, Aedes, 61, 76, 77 Culiseta, 1, 5, 19, 21, 23, 24, 33, 37, 38, 39 curriei, Aedes, 77 cyanescens, Psorophora, 5, 9, 17, 82, 85, 86, 87, 89 Janthinosoma, 87, 89

L 951 96 ILLINOIS NATURAL HISTORY SURVEY BUM. ETIN VOL 24, Art.1

lateratis, Aedes, 79 salinarius, Culex, 17, 42, 43, 44, 45, 49 longipalpis, Psorophora, 82, 84, 87, 90 sapphirina, Uranotaenia, 8, 17, 20, 22, 23, 33 septentrionalis, Megarhinus, 7, 9, 17, 18, 20, 22, 23, 32 signi f era, Bancroftia, 37 Mansonia, 3, 4, 17, 19, 22, 24-, 35 signifera, Orthopodomyia, 17, 18, 20, 22, 23, Megarhinus, 1, 19, 23, 24-, 32 36, 37 melanura, Culiseta, 37 signipennis, Psorophora, 82, 92 Melanoconion, 50 1A'yeomyia, 5, 7, 8, 17, 18, 20, 22, Aedes, 17, 52, 57, 58, 60, 64, mitchellae, 23, 34 65, 70 sollicitans, Aedes, 1, 2, 5, 17, 20, 52, 53, 57, Mochlony-x, 16, 17 58, 60, 64, 65, 67, 69, 70, 77 rnorsitans, Culiseta, 8, 17, 37, 38, 39, 40 spencerii, Aedes, 8, 17, 55, 57, 53, 59, 62, 64, 79 Stegomyia, 65, 66 sticticus, Aedes, 6, 8, 17, 55, 57, 58, 59, 62, Neoculex, 46 64, 68, 76, 78, 79, 80 nigromaculis, Aedes, 17, 52, 57, 64, 70 stimulans, Aedes, 2, 6, 8, 17, 21, 54, 57, 59, 62, 64, 71, 72, 73, 75 sytvestris, Aedes, 68 occidentalis, Anopheles, 25, 26, 27, 28 sylvicola, Aedes, 75 Ochlerotatus, 65, 71 Orthopodomyia, 1, 2, 5, 7, 19, 24, 36, 37

Taeniorhynchus, 65, 69 taeniorhynchus, Aedes, 2, 70 pallens, Aedes, 81 tarsalis, Culex, 17, 19, 41, 43, 44, 45, 46, 49 peccator, Culex, 17, 43, 44, 45, 51 thibaulti, Aedes, 9, 17, 53, 57, 58, 59, 60, 64, perturbans, Mansonia, 17, 18, 21, 22, 23, 35 73, 75 pipiens, Culex, 7, 8, 17, 42, 43, 44, 45, 46, titillans, Mansonia, 35 47, 48, 49 triseriatus, Aedes, 2, 7, 17, 28, 53, 57, 58, Psorophora, 1, 2, 5, 6, 9, 13, 19, 20, 21, 22, 59, 60, 64, 65, 67, 75 24, 82, 33, 87, 88 trivittatus, Aedes, 2, 8, 17, 52, 55, 58, 59, punctipennis, Anopheles, 5, 8, 17, 25, 26, 27, 62, 64, 74, 75, 76 29, 30, 31, 32 punctipennis, Chaoborus, 16 punctor, Aedes, 8, 17, 52, 59, 63, 64, 82 pygmaea, Psorophora, 82 Uranotaenia, 1, 19, 23, 24, 33, 51

quadrimaculatus, Anopheles, 1, 2, 9, 17, 20, 23, 25, 26, 27, 28, 29, 30, 31, 32 varipes, Psorophora, 9, 17, 20, 22, 86, 90, 91 quinquefasciatus, Culex, 7, 8, 9, 17, 42, 43, vexans, Aedes, 2, 5, 6, 7, 8, 17, 20, 54, 57, 44, 45, 46, 48, 49 58, 59, 60, 65, 67, 68, 69, 76, 79, 88, 89

restuans, Culex, 2, 7, 8, 17, 23, 41, 43, 44, walkeri, Anopheles, 5, 8, 17, 2:1, 26, 28, 45, 46, 47, 48 29, 30 rutilus, Megarhinus, 32 Wyeomyia, 2, 17, 19, 20, 21, 24, 34 RECENT PUBLICATIONS A.--1LLIN'OI$ NATURAL HISTORY SURVEY BULLETIN+ Volume 22, Article 10—The Plant Bugs, or Miridaa, of Illinois. By Harry H. Knight, September, 1941. 234 pp.!, frontis. + 181 figs,, bibliog., index.. ✓ehime 22, Article 2,—Studle5 of North American Pleeoptera, with special refexenco to the fauna of Illinois. By T. H. Prison. September, 1942. 122 pp.., front's, + 126 figs., hibliog., inifex, ;1,1)0. -Volume 22, Artiele 3...—rdiinagereent 0,1 Small Artfileial Lak es: a summery of fiisheitie bkvestigarlting, 193B-1942.. By George W., aunnett. tEbraaryR 1948, 20 pp., frcintis. + 7 h.gs, bibliog. ✓olume 22., ArLiele 4.—The Prairie Cbicken in By Ralph E. Tectter. May, 1943. 40 pp...iron:4s. + J3 flgs PfbIIoz. (Buumd with Article S.) Arelume 22, Artiele l'irsfetentiat Rating of Duck Food Plants, By Frank C. Bell- rose, Jr., and Harry G. .Andereen. May, 1$43. 1.6 pp., frontis. 13 bga.. bibliog. (Bound with Article 4.) Volume 22, Article 6.—Supirey of the Illinois Fur Resource. By L131.315 G. Brow-B, and Lee E. Yeager. September, 2.614a. 74) pp., frontiA,. 3.3 ng5., bibliog. (Round with Article 7.) Volume 22, Article Furhearer DiNtribution arid Income. By Carl 0,. leohr, September, 1943. 32 pp., frontisi ± 24 tip... bibliog. tBound with Article 6,4 VEllume 22, kruiele L—The Caddie flie or Trichoptera, of Illinois, By Herbert H+ Itchw Auroa, 15144. 326 pp„ frontia. 981. Index, $1..5.0. Volume 23, A.rtiEle 2,—Duck Populations and Kill. By .b1rank C. Bellrose, Jr. Novem- ber, 1.944, 48 pp., frorati& ÷ 27 tig5., Volume a, Article .3.—Overriablua in a Small Artificial Lske; Onized Lake near Alton, 11H . By George W+ Bennett. May, 1945. 24 pp,I, froaisi. + 15 Ags„ Volume 2S, Article 4.—Wetwood of Ehns. By J. Cedric Carter. Augu5t, 1945. 42 pp, front:is, SO figs., bibliog.. Volume 23, Araele .5.—Pux Squirrels arid Gray &Myra! in Loui 9 G. Brown anci Lee E. ?eager. pthmber., 1046. 88 pp., frontis. -h 42 figs..., B.—ILL,INO19 NATURAL HISTORY SURVEY CIRCULAR. -Pleasure With Plants. By L. IL Telion.. November, I.942. (Sereond printing, with. rev-Worm.) 32 pp., frontis. figs, 20..—Cartro1l[ng Peach Inceets hi Illinois. By Si C. Clkergarr and W. P. mint. Augusts 1939. 40 pp, frontia. 1- 32 figs. 24.—Rout ake Weeih.! Why, When and. Bow, Bsr L. R. Tenon. September, . 1946. (Fourth printing, with revisions.). 47 coIer fron,. ± 12 HO. SO.—How to Collect and Preserve! Iimuct.t. By H. H. Rem May, 1944, (Second printing, with additions.) .55 rip„ frontis. 6.3. t . -11.—Iiow to Recornize and Control Termites in Illinois. By B. 6, Berger_ February, 1 .11.. 44 pp,, fronds. + 32 figs. C.--ILLINOIS NATURAL HISTORY SURVEY MANUAL. 2.—Fie1dboak ef Illinois Land Snails. By Itratik Collins Bakor AigijL, On% 165 mr., color [rout's. -h 170 figs., 8 isle+ $1,00. 34---Fickihouic oF Ntitive Shruba. By Leo 11. Tchon. December., 1042. an pp., 4 color pls. + 72 Tip., glimmary, index.

1.41 of dwaiLakil. lIIl Q kii obviig IVY CIAO.. 1THJD FT rdqu.amg , Address orders and correspiendente hi t_13 Chief ILIMOIS NATURAL HiSTORI SuRvEy Natural Resources Building, Urbane. Illinois rallimmt tn 121.6 Coirm AL,. S. PAIL Ofergt GLOOMY order ramie BAIT ta 'STOUR Tre_asurrir nf Eil liduiflad, intiokL, mtiil ardziorariaasy requesta Lar thosti pahllea DEmo eppi wildi ch 6 PAre II.. %AT,