The Yalue of Prebaceous Beetles in Bestroying Insect Pests

THE YALUE OF PREBACEOUS BEETLES IN BESTROYING INSECT PESTS.

By A. F. BURGESS and C. W. COLLINS, Of the Bureau of Entomology.

WORK ON PARASITIC ENEMIES OF INSECT PESTS. During the past few years much attention has been paid to the value of the parasitic enemies of some of our common destructive insect pests, but the greater part of the work has been attempted for the purpose of introducing into this country, or transporting from one part of the country to another, natural enemies which appear to be necessary in order to bring about the control of destructive specie^ which are new in the locality where the damage is most noticeable. As early as 1883 a few beneficial species were introduced into this country by the Division of Entomology, now the Bureau of Ento- mology, United States Department of Agriculture, and since that time the work has been carried on intermittently whenever there seemed to be an opportunity to secure some valuable natural enemies of destructive insects. Similar work has been attempted and carried on continuously for a number of years by the board of horticulture of California, and, more recently, the Hawaiian Sugar Planters' Experi- ment Station at Honolulu has taken up this line and has succeeded in introducing several enemies of insects which affect sugar cane. The largest attempt of this sort is now being made by the State of Massa- chusetts in cooperation with the Bureau of Entomology of the United States Department of Agriculture in an attempt to secure the parasites and natural enemies of the gipsy and brown-tail moths in Mas- sachusetts. These insects were introduced from Europe a number of years ago and since that time have caused widespread destruction to orchards and forests.

USEFULNESS OF PREDACEOUS BEETLES. It is not the purpose of this article to discuss parasite work, but to ' point out one phase of it that is seldom given marked prominence, namely, the value of predaceous beetles. Strictly speaking, they are not parasites, but are often classed as such for convenience, as they are carnivorous and destroy their prey by feeding upon it externally, and in this way accomplish the same object but in a different manner from that of the true parasites, the larvae of which feed internally upon the host. 453 454 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE.

Among our native beetles that are predaceous in habit are several species which belong chiefly to two families, namely, the Carabidse, commonly known as ground-beetles, and the Coccinellidse, or ladybirds. It is true that the tiger-beetles (Cicindelidse) and some species of Tenebrionidae are predaceous and that certain elaterids undoubt- edly have similar habits, although very few observations have been made to show how much they accomplish in destroying insect pests. The larvae of many of those already referred to are also predaceous, and this renders each species more effective in reducing and bringing under control injurious insects. June 15, 1910, Mr. H. S. Barber observed near Melrose Highlands, Mass., a small burrow in the ground which contained a larva of one of the tiger-beetles, probably Cicindela 6-guttata Fab. Surrounding the mouth of the burrow (PI. LXII, fig. 1) were the remains of 10 partly grown gipsy moth caterpillars which had been partially eaten by the beetle larva and cast from the burrow. Since that time we have attempted to determine whether adults of this species when kept in captivity would feed upon caterpillars. In each case a few caterpillars were eaten, but the beetles do not live long under such conditions, so that it is a difficult matter to ascertain the amount of food which they normally consume. There are several families of predaceous beetles the adults of "which live in ponds and streams. Some of these are known to feed on young fish, and in this way they may cause injury rather than benefit. The two principal families, however, about which the most is known are the Carabidse and the Coccinellidae. Among the latter are a large number of species which are common in most regions of the United States.

BENEFICIAL WORK OF NATIVE LADYBIRDS ( COCCINELLID^ ).

Several species, such as A dalia hipunctata L. (fig. 15), the two- spotted ladybird, and various species of the genus Coccinella and other closely related genera feed principally on plant-lice, insects belonging to the family Aphididae, but sometimes attack small larvas of various sorts. Owing to their enormous reproductive capacity, the plant-lice are often very serious pests^ as many generations are produced in a single year, and great damage would result to the crops or trees on which they feed unless their increase were checked by natural enemies or by hand suppression. The latter is seldom necessary, however, owing to the effectiveness of the former, but occasionally, when conditions are unfavorable for the increase of ladybirds, the damage is very great. VAIiUE OF PEEDAOEOUS BEETLES. 455 Nearly every spring plant-lice are abundant on some one or more of our common cultivated crops, or trees and shrubs. The apple aphis (Aphis mali Fab.; fig, 16), is sometimes very abundant and causes

FIG. l^.—Adalia Upunctata: a. Larva ; h, mouth parts of same ; c, claw of same ; d, pupa; 6, adult; f, antenna of same. All enlarged. (From Marlatt.) serious injury to apple trees, especially to seedlings and young stock in nurseries. It seldom becomes noticeable until the leaves on the terminal twigs or shoots begin to curl (fig. 17), owing to the presence

FIG. 16.—The apple aphis (Aphis mali) : a. Winged agamic form ; h, pupa ; c, wingless agamic form ; d, recently born aphis. All greatly enlarged. (From Quamtance.) of large numbers of the aphides which are feeding on the sap. Be- fore the injury proceeds very far the increase of the plant-lice is usually prevented by the inroads made upon their numbers by the more common species of ladybirds, which in both adult and larval 456 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE.

forms feed upon these pests. It is true that some species of aphides are controlled almost completely by parasites and many are preyed upon by syrphids and lace-wing flies. The value, however, of ladybirds in accomplishing the control of many of our common species of plant-lice has never been overestimated, and it is probable that too little credit has been mven these beneficial insects.

FIG. 17.—Terminal shoot of apple infested with the apple aphis (Aphis mali), showing condition of leaves. (From Quaintance.)

Early in the spring of 1898 Mr. A. F. Burgess observed in Maiden, Mass., that the gray birches over a considerable area were thickly cov- ered with small, black aphidid eggs. These were kept under obser- vation for several weeks, and as soon as the weather became a little warmer, about the middle of April, several species of ladybirds, the principal ones being Adalia hlpiinctata L., Cocchiella sanguínea L., Yearbook U. S. Dept. of Agriculture, 19t 1. PLATE LVII

SALTlMOtlB.

SOME NATIVE AND IMPORTED SPECIES OF CALOSOMA. FIG. 1. —Calosoma scrutator. FiG. 2. —Calosoma wiUeozi. Via. 3. — Calosoma frigidum. FIG. i. —Calosoma ealidum. FIG. S. —Calosoma exiernum. FiG. 6. —Calosoma lugubre. FIG. 7. — Calosoma semilm>c. FIG. 8. — Calosoma sayi. FiG. 9. — Calosoma maximowiczi. FIG. 10. —Calosoma chirw.nse. FIG. 11. — Calosoma auropunctatum. FIG. 12. — Calosoma reiiculatum. FIG. IS.—Calosoma inquisitor. Natural size. (Original.) Yearbook U S Depf of AgricuHure, 1911. PLATE LVIII.

THE GIPSY MOTH IPORTHETRIA DISPAR. Fig. 1.—Male moth. Fit;. 2.-Female moth. Fig. .3.—Male pupa. Fig. 4.—Female pupa. Fig. .ï.—Egg cluster. Fig. u.—Caterpillars; the largest are less than half grown. (From Rogers and Burgess.) VALUE OF PREDACEOUS BEETLES. 457

G, 9-notata Herbst (fig. 18), G, trifasciata L., and Anatis 15-punctata Oliv., made their appearance in large numbers and fed freely on the ç^gg masses. Numerous experiments were made to determine the number of eggs that were consumed by one of these beetles, as it was apparent that the development of the aphidid was being seriously checked by the destruction of the eggs before hatching. Control experiments showed that an ^à\x\t Adaliahipunctata^x^YdigQà to destroy 100 aphidid eggs daily. Owing to the enormous number of eggs that had been deposited the previous fall it was inevitable that a large number of the aphidids would escape, but these were followed up by the ladybirds and their larvae, so that before midsunimer it was almost impossible to find a specimen in the region which had been badly infested, and in the fall the eggs of this species could be found on the trees only after prolonged search. In this case the aphidid was brought under complete control by ladybirds. During the spring feeding experiments were conducted to determine the number of aphidids which were being consumed by the various species of Cocci- nellidae which were found abundantly among the infested trees. As a result of FIG. 18,—Coccînella 9-notata: /, Adult; g, larva of this work it was determined ^^°^^- ^" enlarged ; size indicated by hairline at riifht. (From Chittenden.) that on the average each beetle destroyed 60 aphidids daily, while the average number killed by each beetle larva amounted to 53 daily. The number of eggs laid by a single fernale of various species of ladybirds, when in captivity, ranged from 19 to 426, and seemed to depend largely upon food supply. The length of time required to develop a generation in early summer was from 30 to 52 days, depending upon the species. It is interesting to note that several somewhat similar experiments were conducted by Dr. S. J. Hunter, in 1907 and 1908, in connection with his studies on the "green bug" (Toxoptera grammunh Rond.) in Kansas. The results which he secured indicate that a single coccinellid beetle, when kept in captivity, will destroy from 50 to 60 "green bugs" a day, and several records are given where 100 were eaten in the same length of time. A record is given of the food consumed by one coccinellid larva, which averaged 20 " green bugs " a day. The number of eggs deposited by coccinellids depends to a considerable extent on the food supply. Most of the species hibernate as adults during the winter, and it is probable that they are able to 458 YEAKBOOK OF THE DEPARTMENT OF AGEICULTÜRE.

survive for a long time with a small amount of food. As soon, however, as the food supply is abundant a large number of eggs are laid, and the larvae hatch and develop rapidly. In case of a scarcity of food these larvae often destroy each other, or feed upon the eggs deposited by females of the same or other species. The number of generations, therefore, depends largely on the food supply, and this being the case it is never possible for these predaceous species to exterminate the host. There are coccinellids which feed extensively upon those aphidids that secrete a woolly covering for the body, but Chilocoms hivulnerus Muls. and Pentilia misella Lee. (PI. LXII, fig. 2) and closely related species feed on scale insects. These beetles are very beneficial, but the work which they do is not so conspicuous as that of the larger species previously mentioned. It is such work as this, which goes on unnoticed and usually unappreciated, that results in reducing many of our species of common insects so that they never become abundant enough to cause serious injury to trees or crops.

BENEFICIAL WORK OF NATIVE GROUND-BEETLES (CARABID^).

Among the Carabidae are a considerable number of species belonging to Calosoma, Lebia, and other closely related genera which a*re carnivorous in habit and feed for the most part on various species of lepidopterous and other larvae. Most of these ground beetles are inconspicuous, and some of them feed during the night, so that their presence is seldom observed and the good work which they do is usually unnoticed. In northern United States two of the more common species are Calosoma calidum Fab. (PL LVII, fig. 4) and Calosoma frigidum Kirby (PI. LVII, fig. 3). The former is often called "the fiery hunter," and its larva is sometimes known as the cutworm and corn grub killer, owing to the fact that it feeds on cutworms and other larvae which are ordinarily found among the roots of various plants. This species is terrestrial in habit and therefore is of little importance as an enemy of caterpillars that climb trees. On the other hand, adults of Calosoma frigiduTn climb trees and feed upon caterpillars on the trunks and branches. So far as known all the beetles of this genus lay their eggs in the ground. The larvae which hatch from these eggs feed upon cutworms or such other insects as they may be able to secure. Calosom^a frigidum is seldom found outside of wood- land, while Calosoma calidum is more commonly observed in gardens or around cultivated grounds. Two of our native species of Calosoma which are common in the eastern, central, and southern parts of the United States are bril- liant green in color. The larger one, CoHosoma scrutator Fab. (PL VALUE OF PREDAOEOUS BEETLES. 459

LVII, fig. 1), is found in abundance at the electric arc lights in the spring, during the time it flies most actively. Its distribution is local rather than general, and it has been possible to collect a considerable number of specimens around the arc lights in Washington, D. C, during the month of May. The smaller species, which is very similar in color, Calosoma willcoxi Lee. (PI. LVII, fig. 2), is also secured around the lights, but is less common than its larger relative. Calosoma lugubre Lee. (PL LVII, fig. 6) is found in the southern and western portions of the united States, while G. say i Dej. (PI. LVII, fig. 8) is common locally over the entire country, except iïi New England, and has been found as far north as British Columbia. These species resemble Galosonba calidum in habits, inasmuch as they are terrestrial, whereas Calosoma scrutator and Calosoma willcoxi climb the trees and feed upon such caterpillars as they are able to find. Calosoma extemum Say (PL LVII, fig. 5) occurs throughout the United States, except in the extreme northern part and possibly in the Pacific Coast region. The adults climb well and are able to feed in trees. One of the California species, Calosoma semilœve Lee. (PL LVII, fig. 7), is a ground form and feeds on caterpillars in cultivated land. Mr. H. M. Russell, of the Bureau of Entomology, informs us that during the spring of 1910 he captured a larva of this species which was feeding on a cutworm, Pendroma margaritosa Haw., in a sugar-beet field near Compton, Cal. He was able to rear the adult beetle from the larva, so that there is no doubt about the identity of the species. Several other species of Calosoma are found in the United States, but we have not had an opportunity to study live specimens. Of the other species of Carabidae only a moderate number of care- ful observations have been published. The beetles are usually scarce, except in special localities, and it is difficult to secure correct information in regard to them, as they remain in seclusion most of the time and feed to a large extent under the cover of darkness. Some of the species which are least related to Calosoma are known to feed on plants, more especially on the pollen, and it is possible that if this matter were thoroughly investigated it would be found that the beetles accomplish some good by destroying the seeds of some of our more common weeds. In 1883 Dr. S. A. Forbes^ published the results of stomach exami- nations of various species of Carabidse and found that of 175 specimens examined, 57 per cent of the food was of animal origin, 36 per cent being composed of the remains of insects ; the other 21 per

1 The Pood Relations of Carabidae and Coccinellidae. Bui. 6, 111. State Lab. Nat. Hist, 1883. 460 YEAKBOOK OF THE DEPARTMENT OF AGRICULTURE. cent being made up of moUusks, earthworms, myriopods, and Arach- nida. The vegetable matter eaten, amounting to 43 per cent, was composed of the remains of cryptogamic plants and the pollen of grasses and Composite. Species of the genus Calosoma are not able to subsist on food of a vegetable origin. On .the other hand, they are strictly carnivorous, and must eventually perish or migrate in the event of a prolonged absence of such food, although some of them are able to survive several months without animal food. Among the other carabids are a considerable number that consume a greater or less amount of vegetable food, as indicated by the dissections just mentioned, but there is little evidence to show that these insects or any of the coccinellids which are normally predatory in -habit have caused serious injury to vegetation. This being the case, it is probably a distinct advantage that these insects are able to consume enough vegetable food to tide them over when insects upon which they normally feed have been reduced to insignificant numbers. During the summers of 1909 and 1910 it was positively demonstrated that Calosoma frigidum^ together with the minute ^gg parasite Telenomus gmptœ How., brought about effective natural control of the saddled prominent {Heterocampa guttivita Walk.), an insect which had for two years previously completely defoliated thousands of acres of forest lands in Maine and New Hampshire. The serious- ness of this outbreak can be realized when it is stated that in many areas which had been defoliated the trees were beginning to die, especially in the tops, and that the timely checking of this pest prevented the loss of thousands of acres of deciduous forests. In some sections defoliation of sugar-maple trees was so severe that the flow of sap the following spring was curtailed, which greatly. reduced financial returns in the maple-sugar district. Many of the trees were so badly injured that the growth was checked, and as a result the new wood died. Such a condition is always detrimental to tree growth of any kind, inasmuch as it offers favorable breeding places for barkbeetles and other insects which feed upon trees which are weakened from any cause.

FACTS CONCERNING THE IMPORTATION OF SEVERAL SPECIES OF PREDACE0U8 BEETLES. As stated in the first part of this article, many serious attempts have been made to import the natural enemies of various insect pests and to establish them in the region of the adoption of their host. The efforts along this line have been very fully set forth in Bulletin 91, Bureau of Entomology, by Dr. L. O. Howard and Mr. W. F. Fiske, and the importation of predaceous beetles as well as true parasites is there considered. VALUE OF PREDAOEOUS BEETLES. 461

It goes without saying that many of these attempts have been futile in bringing about the suppression of the pests, but each one of them has resulted in increasing our knowledge of the life habits of the insects concerned and has enabled us to secure information which could be utilized in other ways to the enormous advantage of the farmer and the fruit grower, which simply means that the public as a whole has profited by the discoveries made, inasmuch as in the end those who consume the products of the farm or orchard must pay their share in the increased cost of controlling by "hand suppression or otherwise the pests which destroy crops. During the years from 1890 to 1900 the State of Massachusetts ex- pended about $1,000,000 in an attempt to exterminate the gipsy moth. (PI. LVIII.) In the last-mentioned year the work was abandoned by the State and the moth was allowed to increase and spread without interruption for five years, when a more elaborate and expensive campaign was resumed. Although the first work on the moth did not secure the object desired—that is, extermination of the pest^— tlie result of one of the investigations attempted was the dis- covery of the insecticidal value of arsenate of lead, and this material has proved so effect- FIG. 19.—The Australian ladybird {T^ovim ive that to-day it is used in cardinalis), an imported enemy of the fluted nearly every country in the scale : a. Ladybird larvfe feeding on adult female and egg sac ; ô^ pupa ; Cj adult lady- world where spraying opera- bird ; d, orange twig, showing scales arid tions are carried on, and this ladybirds, a-c. Enlarged ; d, natural size. (From Marlatt.) was only one of the practical questions that was solved by the work undertaken by the State of Massachusetts. The same principle applies to the work of investi- gating natural enemies, and while as a rule the results are seldom of as widespread utility as those in the case that has just been mentioned, great and often unforeseen benefits result either directly or indirectly from such experiments. One of the most successful attempts at introducing predaceous beetles was carried on late in the eighties by Mr. Albert Koebele, who secured specimens of Novms cardinalis Muls. (fig. 19) in Aus- tralia and shipped them to California for the purpose of controlling the fluted or cottony cushion scale {Icerya purchasi Mask.), which was then threatening the destruction of the citrus-fruit industry of that State. It is generally conceded that the result of this im- 462 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. portation was the most striking and immediate success which has ever been accomplished from the introduction of natural enemies of insects, as the species rapidly developed and controlled the host. During 1901 and 1902 Mr. C. L. Marlatt, of the Bureau of Ento- mology, conducted investigations in Japan and China for the purpose of determining the native home of the San Jose scale and of securing its parasites or predatory enemies. He concluded that the insect was indigenous to northern China, where it was apparently being controlled by an insect which has since been termed the Asiatic ladybird {GhiloGorus similis Kossi; fig. 20), and he forwarded specimens

FIG. 20.—^The Asiatic ladybird (Chilocorus similis), an imported enemy of the San Jose scale : a^ Second larval stage. Ö, cast skin of same ; Cj full-grown larva ; d, method of pupation, the pupa being retained in the split larval skin ; e, newly emerged adult, not yet colored ; f^ fully colored and perfect adult. All enlarged to the same scale. (From Marlatt.) to this country, a few of which arrived in good condition for propaga- tion. Several colonies of beetles were liberated in various parts of the United States where the San Jose scale was abundant and where conditions appeared to favor their increase. For some unknown reason the species has apparently died out, as no specimens hav€ been found for several years. When the work of suppressing the gipsy moth was resumed in 1905 by the State of Massachusetts an appropriation was made for the purpose of introducing its natural enemies. Later, an arrange- VALUE OF PEEDAOEOUS BEETLES. 463 ment was made whereby the work was taken up cooperatively with the Bureau of Entomology of the United States Department of Agriculture, and Dr. L. O. Howard, chief of the bureau, was given general supervision. Among the attempts which were made to introduce parasites was an effort to secure specimens of two predaceous beetles from Europe, namely, Calosoma sycophanta L. (PI. LIX) and OalosoTYha inquisitor L. (PI. LVII, fig. 13), as they were reported to be quite common in regions where the gipsy moth was abundant and to devour the caterpillars in large quantities. Accordingly, in 1906 these two species were imported in small numbers, a few were colonized in the field, and since that time a much larger number of the former species has been secured, so that it has been possible, by means of rearing and colonization work, to liberate about 18,000 adults and larvae in the area badly infested by the gipsy moth. This work has been carried on since 1906, and at the present time the beetles have been found in greater or less numbers over an area of about 400 square miles. OaZosoina inqidsitor^ however, has not been successfully colonized, although it has been kept in control cages out of doors at the Gipsy Moth Parasite Lab- oratory and has successfully passed two winters. As a result of the ability of Oalosoma sycophanta to withstand winter conditions in New England and reproduce and increase in the field, considerable time has been devoted to securing accurate data on its life history, as this has an important bearing on the utility of the species.

COMPARISON or CALOSOMA SYCOPHANTA WITH NATIVE CALOSOMAS. In this connection several native species of Calosoma have been studied with a view to determining if possible the reason for their failure to become as effective enemies of the gipsy moth as the imported sycophanta. This work has been carried on for several years, and by means of assistance kindly furnished by various entomologists throughout the United States we have been able to secure live specimens of several southern and western species of Calosoma for study and investigation. As a result it has been found that the life his- tories of these species are quite similar and will compare very well with sycophanta^ which has been worked out in detail. The habits of the different species vary considerably, and experiments have demonstrated that the reason why our native species are of small importance as enemies of caterpillars which feed upon the trees and pupate without coming to the ground, is because the larvae of these beetles are not able to climb to a sufficient extent to secure food on the trunks and large branches of the trees. The larvae of sycophanta are able to do this (PI. LX), and it seems to be a fixed habit 464 YEAKBOOK OF THE DEPARTMENT OE AGRICULTURE. of this species for the larvae to feed upon the caterpillars or among masses of gipsy moth pupae on the trunks of the trees. This enables the larvse to secure sufficient food (PI. LXI) so that a marked increase in the number of beetles is found each year. As the larvse of the native species must depend almost entirely upon caterpillars or pupae which they can find on the ground or underneath débris or leaves that have fallen in the woods, rapid increase is not possible unless caterpillars having the habit of crawling or pupating on the surface of the ground become abundant. The results of the investigation of Ccdosoma sycophanta have been published in Bulletin 101 of the Bureau of Entomology, and as most of our native species have a similar Jife history a brief statement is given to show the transformation of the imported species. As adult sycophanta beetles have lived two or three years in captivity and under out-of-doors conditions it is probable that the life period may be longer. The eggs are deposited late in June and during July beneath the surface of the ground and, on the average, about 100 are laid annually by each female. Hatching takes place in less than a week, the young larvae coming to the surface of the ground and crawling about rapidly in search of food. They climb trees readily if the bark is rough and molt twice before becoming full grown. This species is able to molt without descending to the ground, and it is quite common to find cast skins of the larvae on trees where they have been feeding. Full grown sycophanta larvae measure about If inches in length, and the body is very stout. In common with the adult, the larvae feed on caterpillars and pupae of the various Lepidop- tera, but the larvae seem to prefer female pupae, although they are able to kill the largest caterpillars. In feeding they cut through the outer tissue of the caterpillar or pupa with their sharp jaws and feed upon the liquids and soft tissues within. The available data show that a pair of beetles of this species and their progeny will in a single year destroy enough larvae and pupae of the gipsy moth to prevent the deposition of 1,000 egg clusters of that insect. When full grown the larvae enter the ground and make an oval chamber 4 inches or more below the surface. In this cavity pupation takes place and the beetle transforms usually by the middle of Au- gust. The insect does not seek the surface, however, but remains in the cavity throughout the winter and emerges in the spring. In the course of the work of importing parasitic and predaceous enemies which feed upon the gip^ moth, it seemed wise to secure and introduce some of the species of Calosoma from Europe about which little was known except that they were predaceous in habit. The establishment of any beneficial species which is a general feeder is valuable, not only in relation to the problem at hand, but if it is sue- Yearbook U. S. Dept. of Agriculture 1911. PLATE LIX.

CALOSOMA SYCOPHANTA. [A

LARV/E OF CALOSOMA SYCOPHANTA FEEDING ON GiPSY MOTH CATERPILLARS UNDER BURLAP. 11'hutogiuph taken al i'ine Uauks I'ark, Maldeu, Mass., rjlO. (From Uurgess.)] Yearbook U. S. Dept. of Agriculture, 1911. PLATE LXI.

PUP/E OF THE GiPSv MOTH THAT HAVE BEEN DESTROYED BY THE LARV/E OF CALOSOMA SYCOPHANTA. [Note llie irregular holes, which are characteristic. (From Burgess.)] Yearbook U. S. Dept. of Agriculture, 1911. PLATE LXII.

FIG. 1.—BURROW OF TIGER BEETLE LARVA (CICINDELA SEX-QUTTATA SHOWING DEAD AND PARTLY EATEN GIPSY MOTH CATERPILLARS THAT HAVE BEEN KILLED AND EXPELLED FROM THE BURROW BY THIS PREDACEOUS LARVA. NATURAL SIZE. IORIGINAL.)

^ ^

FIG. 2.—PENTILIA ' MICROWEISEA) MISELLA. In Beetle' b larva; c, pupa; d. I.lossom end of pear, showing scales with larvse of MicroWeisoa feediiiR on them, iimi piiji:.' of Micruweisea alluched within the calyx. All greatly enlarged. (From llowar

Although a number of the facts which have been given are well known to some of the readers of this article, nevertheless it seems desirable to call attention to the usefulness of the insects concerned in the hope that more interest may be taken in the subject by the general public, especially among those who are interested in nature and the problems which face us in connection with food production on the farm. It is well occasionally for the virtues of the insects which are working constantly for our benefit to be considered in order that all these creatures may not be classed as our mortal foes. Many of the species mentioned and illustrated in this article are of sufficient size to be seen and recognized readily by the ordinary ob- server, and to him these species should appeal from sentiment and because of the useful mission in which they are engaged.