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Home , Culex, Culex fuscocephala, Culex gelidus, Culex whitmorei

Mosquito Systematics, 26(2):75-96, 1994 Copyright 0 1994 by the American Control Association, Inc.

ILLUSTRATED KEYS TO SPECIES OF CULZX () ASSOCIATED WITH IN SOUTHEAST ASIA (DIPTERA: CULICIDAE)

R. REUBEN’, S. C. TEWARI’, J. HIRIYAN’ AND J. AKIYAMA~

ABSTRACT. Illustrated keys are presented for identification of female mosquitoes of 19 genera occurring in Southeast Asia, five subgenera of C&x, and 16 commonly encountered species of Culex (Culex), nine of which have been incriminated as vectors of Japanese encephalitis. Because members of the C&x vishnui subgroup, which includes some impor- tant vectors, are notoriously difficult to identify as adults, separate adult and larval keys are provided. Notes and distribution on individual species are included.

INTRODUCTION Culex in by Bram ( 1967) and a revision of the subgenus Culex in the Ori- Japanese encephalitis (JE) has become an ental Region by Sirivanakarn (1976). These important public health problem in South- are not widely available and are perhaps too east Asia during the last two decades and has detailed for the field entomologist. In this extended its range, including new areas in paper we provide simple illustrated keys to and (Umenai et al. 1985). There the genera of mosquitoes, the subgenera of is an urgent need for entomologists working Culex, and the common Southeast Asian spe- in operational control programs to be able to cies of Culex S.S. Using these keys, field en- identify the vectors of this flaviviral disease tomologists can distinguish species in order to target their efforts efficiently. Al- from the many culicines which resemble Cu- though several genera of mosquitoes have lex S.S., notably species of the subgenera Lut- been found infected with JE virus, the vast zia Theobald, Culiciomyia Theobald, and majority of the isolations have come from Lophoceraomyia Theobald. species of Culex (Cdex) Linnaeus, several of There are 42 species of Culex S.S. in South- which are recognized as major vectors in the east Asia (Sirivanakarn 1976). However, this region (Pant 1979). Apart from Cx. quinque- key is restricted to 16 common species, most- fasciatus Say, which is strongly anthropo- ly of known or potential importance in the philic, these species feed extensively on cat- natural cycle of JE (Carey et al. 1968, Siri- tle, pigs, and birds, but only occasionally on vanakam 1976, Amerasinghe et al. 1988). The man, and are thus important in maintaining remaining 26 species would not normally be reservoirs of the virus in nature. Pigs and encountered in routine collections, but users birds are recognized amplifying and main- of this key should be alert to the occasional tenance hosts of JE virus (Pant 1979). aberrant specimen that may be a species not Identification of Culex S.S. can be difficult included here and should refer to Sirivan- in Southeast Asia. Since the publication of akams’ (1976) key for correct identification. Barrauds’ (1934) volume in the Fauna of The key can be used in all countries of the British India series, two important mono- region shown in Table 1. graphs have been published: a revision of the Females of the Cx. vishnui subgroup are difficult to identify as adult females. How- l Centre for Researchin , 4, Sarojini ever, because of the importance of members Street, Chinna Chokkikulam, Madurai 625 002, India. of the subgroup in the epidemiology of JE, it 2 Regional Entomologist (Retired), World Health Or- ganization, Regional Office for South East Asia, New is frequently necessary to identify adult fe- Delhi, India. males for virus isolation attempts and other 75 76 MOSQUITO SYSTEMATIC~ VOL. 26, No. 2

Table 1. Distribution of common species of Culex (Culex) in Southeast Asia.

Ban- Ma- gla- Cam- Indo- lay- Myan- Singa- Sri Thai- Viet- Species desh bodia India nesia sia mar Nepal pore Lanka land nam Cx. alienus 0 0 0 0 Cx. annulirostris 0 Cx. bitaeniorhynchus a 0 0 0 0 a l l 0 l l Cx. epidesmus l l 0 ? Cx. fuscocephala l l 0 0 l a l 0 0 a l Cx. gelidus a 0 l 0 a 0 0 l 0 a 0 Cx. infila l 0 a 0 0 0 l l Cx. perexiguus 0 0 Cx. perplexus 0 l 0 0 Cx. pseudovishnui 0 a 0 l l a 0 l l 0 Cx. quinquefasciatus 0 a 0 l l l a 0 l 0 0 Cx. sitiens 0 l l l 0 0 l l l Cx. tritaeniorhynchus l l l l l a l l a l l Cx. vishnui l a l l l 0 a l l l l Cx. whitei l l l l a 0 Cx. whitmorei l a l 0 0 0 l l 0

studies. In places where studies have already of Harrison and Scanlon (1975:Fig. 3E), Mat- been carried out, three species, Cx. tritae- tingly(l971:Figs. 5, 15b), Sirivanakarn (1976: niorhynchus Giles, Cx. pseudovishnuiCol- Figs. 17,20, 35,40), and Tanaka et al. (1979: less, and Cx. vishnui Theobald, commonly Figs. 176, 179, 184, 194). The terminology occur and can be satisfactorily separated us- used follows Harbach and Knight (1980), and ing our key. However, the other three species abbreviations of generic and subgeneric of the subgroup, Cx. alienus Colless, Cx. per- names are from Reinert ( 1975). plexus Leicester, and Cx. whitei Barraud, may be locally common and therefore, when com- NOTES ON SPECIES mencing work in a new area, it is desirable to check the species composition. Because subgroup. This is larval characters are diagnostic, we have pro- a group of large mosquitoes (wing 3.8-5.2 vided both larval and adult keys for the six mm), with the anterior 0.7 of the scutum cov- species of this subgroup. ered with pale beige, yellow, golden, or dark brown scales, in distinct contrast to the pos- terior 0.3 of the scutum. Two species are MATERIALS AND METHODS common throughout the region, Cx. bitae- Keys were prepared after examining spec- niorhynchusGiles and Cx. infula Theobald. imens from the collections of the National There have been two isolations of JE virus Institute of Virology, Pune, and the museum in nature from the former in India (Rodrigues of the Centre for Research in Medical En- 1988), and the species feeds extensively on tomology (CRME), Madurai. Scientists of the birds and pigs as well as on man (Christopher CRME have used these keys in studies of the and Reuben 197 1). It could, therefore, play epidemiology of JE in ricefield ecosystems. an important role locally. Little is known The distribution of the 16 common species about the vectorial potential of Cx. infula, of Culex S.S. in the ricelands of Southeast which has been confused with Cx. bitaenio- Asia is shown in Table 1. The morphological rhynchusin the past. Both have wings heavily terms and abbreviations used in the keys are speckled with pale and dark scales, but the illustrated in Figs. 1 and 2. Some of the il- abdominal terga of Cx. bitaeniorhynchusare lustrations were taken from the monographs marked with apical pale bands only, whereas JULY 1994 77

HEAD ANTERIOR ASPECT

Narrow decumbent

Ant

’ ’ XLgIeI’

THORAX DORSAL - LATERAL Prealar knob Pamtergite 1 / Anterior pnmontorv. Aesothomcic spim

Metoni4ernum Mesokatepisternum - n ?:f a Proeois tern1 Posterior 3 dorsocentml I- 1 a ;.

Prescutelararea *

Mesopostnotum y

Fig. 1. Morphology of female mosquito.

CX. infula has both apical and basal bands and in India (Reuben et al. 1988) and Sri and apicolateral pale patches. Lanka (Amerasinghe et al. 1988). Culex fus- A single isolation of JE virus has been made cocephala may be confused with Cx. quin- in India from a third species, Cx. epidesmus quefasciatus because of the absence of a pale Theobald (Banerjee et al. 1979), which ap- band on the proboscis of both species, but pears to be seasonally common in parts of Cx. fuscocephala is easily distinguished by the northern state, Uttar Pradesh (R.S. So- the alternating pale and dark markings on the man, personal communication), where JE ep- pleuron and absence of pale banding on the idemics occur. It possesses a distinctive api- abdomen. cal pale area on the wing, and the apical Theobald. This species is abdominal terga are largely golden-yellow. considered to be one of the most important Culex fuscocephalaTheobald. This species vectors of JE in , Thailand, Malay- is an efficient vector of JE in Thailand (Gould sia, , and Sarawak (Gould et al. 1962, et al. 1974). Isolations from wild-caught mos- Macdonald et al. 1967, Nguyen et al. 1974, quitoes have been made from that country Gingrich et al. 1992, Peiris et al. 1993). Rel- 78 MOSQUITO SYSTEMATICIS VOL. 26, No. 2

WING

fringe

C -costa Msti -media-three-plus-four RL+5 -radius four- plus-five CuA-cubitus anterior mcu - mediocubital crossvein Rs -radial sector ClP -cubitus po!stffior - radius rm - radiomedial crossvein h -humeral cmssvcin : - radius - one SC -subcosta M -media R2 - radius - two sc-r -subcostal crossvein 1A -anal vein MI -media-one R2+3 - radius -two-plus-three M1+2-media-one-plus-two R3 - radius -three M2 -media-two

Fig. 2. Morphology of mosquito wing.

atively few isolates have been made in India absence of a pale band on the proboscis. In (Reuben et al. 1988). It can be distinguished addition, there is a median longitudinal pale from all species except Cx. whitmorei (Giles) stripe on the midfemur. by the pure white scaling on the vertex and Culex quinquefasciatus. A few isolations the anterior portion of the scutum. The ab- of JE have been made from several countries, sence of pale scales on the fore- and midfem- including India and Vietnam, but the species ora separates it from Cx. whitmorei. is regarded as a poor vector and not of im- Culex mimeticus subgroup. This is a group portance in the natural cycle of disease (Sir- of species with spotted wings. It is of no known ivanakarn 1976). The characteristic features medical importance, but species of the sub- are the absence of a pale band on the pro- group are likely to be encountered in foothill boscis and the presence of basal pale bands villages. on the terga. Culex perexiguus Theobald (formerly Cx. Wiedemann and Cx. annu- univittatus Theobald). This species extends lirostris Skuse. Separation of females of these as far as (= Burma) from the east- two species is difficult. Both have hindfemora ern Mediterranean and Ethiopian regions, heavily speckled with dark and pale scales where it is a vector of (Har- anteriorly. However, neither has any known bath 1988). It is not a vector of JE, but it is medical importance in Southeast Asia (Siri- widespread, though not common. In our ex- vanakarn 1976). Culex sitiens is a common perience, it needs to be carefully distin- pest mosquito in coastal areas. Culex annu- guished from Cx. quinquefasciatusand Cx. Zirostrisis an Australasian and Pacific species pseudovishnui,which it superficially resem- that in our region only occurs on some islands bles. It differs from the former by the pres- of and adjacent to Papua New ence of a patch of pale scales on the post Guinea. It has been found to be naturally spiracular area and from the latter by the infected with JE virus in (Pant 1979) JULY 1994 79 and with Sindbis and Murray Valley enceph- speckling of pale scales on wings and femora alitis viruses in (Doherty et al. in many specimens from southern India to 1963). none in parts of Southeast Asia. The scutal subgroup. This group con- scaling varies from pale or golden to beige tains three important JE vectors. Culex tri- and light brown. There is a poorly contrasted taeniorhynchus is extremely common and dark stripe on the anterior dorsal surface of widespread. It has been incriminated as a ma- the hindfemur. Culexpseudovishnuitypically jor vector in India, Sri Lanka, Thailand (Ro- has pale to golden scaling on the scutum, of- drigues 1984, Leake et al. 1986, Amerasinghe ten forming a definite pattern, and the dark et al. 1988, Gingrich et al. 1992), Sarawak stripe on the anterior surface of the hindfe- (Macdonald et al. 1967), and outside the re- mur is generally sharply contrasted with the gion in , Korea, and (Pant 1979). pale areas. However, there is an overlapping It can be easily identified by the dark brown of characters in a proportion of specimens. scaling on the vertex and scutum, the acces- The larvae of these species are distinctive, sory pale patches basal to the pale band on and identifications should always be con- the ventral surface of the proboscis, and the firmed by individual rearings before starting narrow apical dark ring on the hindfemur. studies in new areas. In India it was possible Culex vishnui is also extremely common to identify correctly all except 12% of the and is known to be a vector in India, Thai- adult catch (Reuben 1969). land, and Taiwan (Carey et al. 1968, Cates . Several isolations of JE and Detels 1969, Leake et al. 1986). Culex have been made from this species in India pseudovishnuihas been implicated in south- and Sri Lanka (Carey et al. 1968, Peiris et al. ern India and Sri Lanka (George et al. 1987, 1993), where it may play a role as a secondary Peiris et al. 1993). The role of the latter two vector. This species is similar to CX. gelidus, species in the transmission of JE virus in oth- having pure white scales on the vertex and er countries of Southeast Asia has not been scutum, but the pale scaling extends poste- established, partly because of the difficulty of riorly to the prescutellar space and scutellum, telling them apart as adult females. Culex and there is a speckling of pale scales on the vishnuiis a very variable species, with heavy fore- and midfemora.

KEY TO THE GENERA OF MOSQUITOES IN SOUTHEAST ASIA (Females)

Proboscis rigid, apical half more slender and bent downward; posterior margin of wing emarginate just beyond CuA (Figs. 3, 4) ...... Toxorhynchites Proboscis and wing otherwise ...... 2 80 MOSQUITOSYSTEMATICS VOL. 26, No. 2

2(l). Scutellum evenly rounded; palpus about equal to the length of proboscis(Figs. 5, 6); abdomen with sterna and usually terga largely or wholly devoid of scales ...... - Scutellum trilobed (Fig. 1); palpus short; abdominal sterna and terga with dense, uniform covering ofscales ...... 3

Fig. 6.

Fig. 5.

3(2). Tip of proboscisswollen, upturned, and hairy (Fig. 7) ...... Malaya Tip of proboscissometimes swollen, otherwise unmodified ...... 4

4(3). Scutum with double median longitudinal stripe of broad, flat, usually white or silvery scales;pre- spiracularsetae present; postspiracularsetae absent ...... Topomyia Without this combination of characters ...... _...... 5 j(4). Upper calypter bare; vein 1A reaching wing margin at or before level of base of crossvein mcu (Fig. 8) ...... 6 Upper calypter fringed; vein IA reaching wing margin well beyond level of base of crossvein mcu (Fig. 9) ...... 7 81 JULY 1994

...... Hodgesiu Outstanding scaleson outer half of wing with emarginate tips (Fig. 10) W)...... Urunotaenia - Wing scalesnormal (Fig. 8).

Fig. 10.

...... 8 Prespiraculararea with setae and sometimes scales(Fig. 11) 7(5X ...... 9 - Prespiraculararea bare (Fig. 12) ......

Fig. 12. Fig. 11. 82 M~SQUITOSYSTEMATICS VOL. 26, No. 2 g(7). Remigium and base of subcosta on ventral side without setae; at most 1,2 small prealar setae (Fig. 13)...... _...._...... _..._...... Tripteroides - Remigium and base of subcosta on ventral side with setae; many prealar setae (Frg. 14) ...... Culiseta

Fig. Fig. 14.

9(7). Antenna short, thick, and tapering; mid- and hindfemora with large tufts of suberect scales at apex (Figs. 15, 16) ...... _. . . . _...... Aedeomyz - Antenna and femora otherwise ...... _. _ ......

Fig. 16.

lO(9). Mesopostnotum with a group of small setae; scutum covered with flat scales, usually with bright metallic reflections (Fig. 17) ...... Heizmannia - Mesopostnotum and scutum otherwise . . , ...... 11

Fig. 17. 83 JULY 1994 ll(l0). Fore- and midtarsomere 1 distinctly longer than tarsomeres 2-5 together (Fig. 18) . . . . . Orthopodomyia Tarsomeresotherwise ...... 12

Fig. 18.

...... 13 12(11). Postspiracular setae present, or foreungues toothed, or both (Figs. 19, 20) . . . . 16 Postspiracular setae absent; ungues simple (Figs. 21, 22) ......

Fig. 20. Fig. 19. Fig. 21.

. . . . Mansonia 13(12). Wing with broad, often asymmetrical scales; dark and pale scales intermixed (Fig. 23) ...... 14 Wing with normal scales ......

Armigeres 14( 13). Proboscis curved and laterally compressed (Fig. 24) ...... 15 Proboscis slender and usually straight, never laterally compressed (Fig. 25) ...... VOL. 26, No. 2 84 Mos~urro SYSTEMATICS

Fig. 25.

15(14). Upper calypter bare, alula with broad scales; overlapping silvery scales on interocular space; post- pronotum without scales (Figs. 26-28) ...... _ , ...... Udaya Without this combination of characters ...... Aedes

Fig. 28. Fig. 27. w

16( 12). Antenna with flagellomere 1 about 3 times length of flagellomere 2; alula fringed with narrow scales (Figs. 29, 30); palpus less than 0.2 length of proboscis; scutellum with narrow scales only; wing with anterior fork cell as long as or longer than vein Rzf3; small or very small species ...... , Ficalbia Without this combination of characters ...... , . . . . , ...... 17

Fig. 30.

Fig. 29. JULY 1994 85

17( 16). Alula bare or with flat, decumbent scales (Fig. 3 1); proboscis usually swollen ...... Mimomyia Alula with narrow fringe scales (Fig. 30) ...... 18

18( 17). Hindtarsi with ungues very small and inconspicuous; pulvilli present (Fig. 32) ...... Culex Hindtarsi with ungues not very small; pulvilli absent (Fig. 33); yellow or yellowish brown mosquitoes ...... Coquillettidia

I Fig. 32.

KEY TO THE SUBGENERA OF CULEX IN SOUTHEAST ASIA (Females)

1. Four or more strong lower mesepimeral setae present (Fig. 34); large species ...... Lutzia - Lower mesepimeral setae absent or 1,2 weak ones (Fig. 35); small to moderate species ...... 2

w Fig. 35. 86 MOSQUITOSYSTJZMATIC~ VOL. 26, No. 2

2(l). Pleuron with distinct scale patches on at least upper and lower mesokatepisternumand anterior mes- epimeron(Fig.36) ...... _...... _...... Culex - Pleuron without distinct scalepatches (Fig. 37) ...... _...... 3

3(2). Acrostichal setaewell developed on scutum (Fig. 38); small, dark species;usually without pale bands on abdominal terga , ...... , ...... Eumelunomyia - Acrostichal setae not developed except at extreme anterior end (Fig. 39) . . , ...... 4

Fig. 38.

4(3). Scalingon scutum sparse,rough in appearance;usually small, dark species , ...... Lophoceruomyia3 - Scaling on scutum very dense, smooth in appearance;vertex with broad scalesforming a border to eyes (Fig. 40); moderate sized species ...... , ...... Culiciomyia

3 Females of Lophoceraomyiagenerally are collectedin associationwith males, which are distinguishedby possessing modified tufts of scalesand setaeon one or more flagellomeresof the antenna. Their presenceis usefulin confirming the determination of females. JULY 1994 87

Fig. 40.

KEY TO THE COMMON SPECIES OF CULEX (CULEX) IN SOUTHEAST ASIA (Females)

1. Proboscisand tarsi without pale rings; 1 or 2 lower mesepimeral setaepresent (Fig. 41) ...... 2 Proboscisand tarsi with pale rings (Figs. 42, 43); lower mesepimeral setaeabsent ...... 4

Fig. 42.

Fig. 43.

31). Abdominal terga without pale bands, occasionally a few indistinct bands on posterior segments; pleuron with striking pattern of dark and pale stripes (Fig. 44) ...... jiiscocephafa Abdominal terga with basal pale bands; pleuron without striking pattern of dark and pale stripes (Figs. 45, 46) ...... 3 88 MOSQUITO SYSTEMA~CS VOL. 26, No. 2

3(z). Postspiracular area with pale scale patch (Fig. 47) ...... perexiguus Postspiracular area without pale scale patch (Fig. 48) ...... quinquefasciatus

Fig. 47. w w Fig. 48. JULY 1994 89

4(l). Wing with pale spots on at least 2 areas of costa and 1 area of other veins (Fig. 49) . . Mimeticus Subgroup - Wing without distinct pale spots ...... 5

Fig. 49.

5(4). Abdominal terga II-VIII largely yellowish or golden; pale yellow scales on apical portions of wing veins C, R,, R,, R,, and R,,, forming apical pale area (Figs. 50, 5 1) ...... epidesmus Abdominal terga II-VIII with dark and pale bands, or completely dark; wing tip without definite palearea...... 6

Fig. 50.

Fig. 51. 90 MOSQUITO SYSTEMATICS VOL. 26, No. 2

8(6X Anterior 0.7 of scutum covered with pure white scales ...... 9 Anterior 0.7 of scutum covered with beige, yellow, golden, or dark scales ...... 10 9(g). Anterior surfaceof fore- and midfemora without specklingof pale scales;scales on prescutellarspace, behind wing base, and on scutellum entirely dark; pale band on proboscis narrow, less than length of basal dark area (Figs. 55-5 7) ...... gelidus - Anterior surface of fore- and midfemora speckled with pale scales; scales on prescutellar space, behind wing base, and on scutellum mainly pale; pale band on proboscisbroad, as long as or longer than basal dark area (Figs. 58-60) ...... whitmorei

Fig. 58. JULY 1994 91

1O(8). Anterior surface of fore- and midfemora speckled with several pale scales, at least on apicodorsal surface ...... 11 - Anterior surface of fore- and midfemora entirely dark ...... 12 1 l( 10). Wing scales mainly dark; scutal integument dark; speckling of pale scales on femora contrasting sharply with dark-scaled area (Fig. 6 1) ...... sitiens,annulirostris - Wing with few to several scattered pale scales; scutal integument light brown; speckling of pale scales on femora not contrasting sharply with dark-scaled area (Fig. 62) (see key to Vishnui Subgroup) vishnui

12(10). Erect scales on vertex and scales on anterior 0.7 of scutum entirely deep brown; proboscis often with accessory pale patches on ventral surface, proximal to median pale ring; hindfemur pale with distinct, narrow dark ring distally (Fig. 63) (see key to Vishnui Subgroup) ...... tritaeniorhynchus - Erect scales on vertex usually pale in center and dark laterally; scutum largely pale beige, yellow, or golden-scaled; proboscis without accessory pale patch; hindfemur with pale stripe on anterior surface contrasting well with dark areas (Fig. 64) (see key to Vishnui Subgroup) ...... pseudovishnui

KEY TO THE SPECIES OF THE VISHNU1 SUBGROUP IN SOUTHEAST ASIA (Females)

1. Wing entirely dark-scaled ...... 2 Wing with few to several scattered pale scales, at least on base of vein C ...... 3 2(l). Proboscis longer than forefemur; prescutellar space entirely pale-scaled (Fig. 65); integument of scutum light brown ...... whitei Proboscis shorter than or as long as forefemur; prescutellar space usually with dark scales (Fig. 66); integument of scutum dark brown to blackish ...... perplexus 92 MOEQUITO SYSTEMATICS VOL. 26, No. 2

Fig. 65. Fig. 66.

3(l). Proboscis usually with accessory pale patches or stripe on ventral surface; hindfemur pale with an apical dark ring (Figs. 63, 67); erect scales on vertex all dark . . _ ...... tritaeniorhynchus - Proboscis without accessory pale patches or stripe; hindfemur with dark and pale areas, with or without speckling, but not with apical dark ring; erect scales on vertex mixed pale (cream, pale yellow, or beige) and dark, rarely all dark ...... 4

Fig. 67.

4(3). Anterior surface of hindfemur with pale stripe contrasting well with dark-scaled area (Fig. 64) ...... 5 - Anterior surface of hindfemur with pale stripe not contrasting with dark-scaled area (Fig. 62) ...... vishnui 5(4). Prescutellar area entirely covered with pale scales (Fig. 65) ...... pseudovishnui - Prescutellar area mainly with dark scales (Fig. 66)...... alienus

(Fourth-stage larvae)

1. Individual comb scales apically rounded (fan shaped), fringed with subequal spicules; siphonal tufts weak, with 2-5 branches (Figs. 68, 69)...... , ...... tritaeniorhynchus - Individual comb scales with a well-developed median apical spine and short, subequal lateral spicules (Fig. 70); siphon tufts variable ...... 2

Fig. 68. JULY 1994 93

2( 1). Pleural area of thorax with spicules; about 22 comb scales; siphonal subventral tufts strong, with 6 or more branches (Figs. 70-72) ...... vishnui - Pleural area of thorax without spicules; subventral tufts of siphon with 5 or less branches ...... 3

3(2). About 40 comb scales; subventral tufts of siphon usually bifid, weak, short, length equal to or less than the siphonal width at their point of attachment (Fig. 73) ...... whitei - About 25 or fewer comb scales; subventral tufts strong, greater than siphonal width at their point of attachment ...... 4

Fig. 73.

4(3). Proximal subventral tufts of siphon long, strong, greater than 3 times width of siphon at their point ofattachment(Fig.74) ...... alienus - Proximal subventral tufts less than 2 times width of siphon at their point of attachment ...... 5

Fig. 74. VOL. 26, No. 2 94 MOSQUITO SYSTEMATICS

5(4). Comb scales 4-8 (rarely up to 19), large, strong, spiniform, approximately in a single row; abdominal seta 6-V,VI with 3 branches; siphon lightly to strongly curved (Figs. 75-77) ...... pseudovishnui - Comb scales 12-20, short, arranged in 2,3 irregular rows; abdominal seta 6-V,VI bifid; siphon slender, perplexus straight(Figs. 78-80) ......

I Fig. 76. ” IN\

Fig. 75. Fig. 77.

Fig. 79. JULY 1994 95

ACKNOWLEDGMENTS dae). Contrib. Am. Entomol. Inst. (Ann Arbor) 2( 1): l-296. We are grateful to E.L. Peyton and R.E. Carey, D.E., R. Reuben and R.M. Myers. Harbach, Walter Reed Biosystematics Unit, 1968. Japanese encephalitis studies in Smithsonian Institution, Washington, DC, Vellore, South India. Part I. Virus isolation for many helpful suggestions on other keys from mosquitoes. Indian J. Med. Res. 56: that were used to develop our keys and also 1309-1318. for granting permission to reproduce illustra- Cates, M.D. and R. Detels. 1969. Japanese tions from articles and monographs pub- encephalitis virus in Taiwan: preliminary lished by the Walter Reed Biosystematic Unit evidence for Culex annulus Theob. as a and its predecessors, the South East Asia vector. J. Med. Entomol. 6:327-328. Mosquito Project and Medical Entomology Christopher, S. and R. Reuben. 197 1. Stud- Project. These include publications by S. Siri- ies on the mosquitoes of North Arcot Dis- vanakam, P.F. Mattingly, B.A. Harrison, J.E. trict, Madras State, India. Part 4. Scanlon, and Kazua Tanaka and colleagues. preferences as shown by precipitin tests. J. We are very grateful to R. Rajendran, K. Ay- Med. Entomol. 8:3 14-3 18. anar, A. Munirathinam, and A. Venkatesh Doherty, R.L., J.G. Carley, M.J. Mackerras for help in preparing the manuscript. Special and E.N. Marks. 1963. Studies of ar- thanks are due to K. Pazhaninathan for pre- thropod-borne virus infections in Queens- paring the illustrations. We also thank two land III. Isolation and characterization of anonymous reviewers for their helpful com- virus strains from wild-caught mosquitoes ments and suggestions. Funds were provided in North Queensland. Aust. J. Exp. Biol. by WHO, SEARO, New Delhi under allot- Med. Sci. 4 1: 17-40. ment No. SE ICP VBC 00 1 RB9 1. George, S., J.P. George and J.A. Rao. 1987. Isolation of Japanese encephalitis and West Nile viruses from mosquitoes collected in Kolar District of Kamataka state during REFERENCES CITED 1977-79. Indian J. Med. Res. 85:235-238. Amerasinghe, F.P., J.S.M. Pen-is, S.H.P.P. Gingrich, J.B., A. Nisalak, J.R. Latendresse, Karunaratne and P.H. Amerasinghe. 1988. J. Sattabongkot, C.H. Hoke, J. Pomsdhit, Epidemiology of the 1987 Japanese en- C. Chantalakana, C. Satayaphanta, K. cephalitis outbreak in Anuradhapura area. Uechiewchamkit and B.L. Innis. 1992. II. Entomological aspects. Proc. Sri Lanka Japanese encephalitis virus in Bankok: fac- Med. Assoc. 101:22-23. tors influencing vector infections in three Banerjee, K., P.V.M. Mahadev, M.A. Ilkal, suburban communities. J. Med. Entomol. A.C. Mishra, V. Dhanda, G.B. Modi, G. 29~436-444. Geevarghese, H.N. Kaul, P.S. Shetty and Gould, D-J., H.C. Bamett and W. Suyemoto. J.P. George. 1979. Isolation of Japanese 1962. Transmission of Japanese enceph- encephalitis virus from mosquitoes col- alitis virus by Culex gelidus Theobald. lected in Bankura district (West Bengal) Trans. R. Sot. Trop. Med. Hyg. 56:429- during October 1974 to December 1975. 435. Indian J. Med. Res. 69:201-205. Gould, D.J., R. Edelman, R.A. Grossman, Barraud, P.J. 1934. The fauna of British A. Nisalak and M.F. Sullivan. 1974. India, including Ceylon and Burma. Dip- Study of Japanese encephalitis virus in tera. Vol. V. Family Culicidae. Tribes Chiangmai Valley, Thailand. IV. Vector Megarhinini and . Taylor and studies. Am. J. Epidemiol. 100:49-56. Francis, London. Harbach, R.E. 1988. The mosquitoes of the Bram, R.A. 1967. Contribution to the mos- subgenus Culex in southwestern Asia and quito fauna of Southeast Asia. II. The ge- Egypt (Diptera: Culicidae). Contrib. Am. nus C&x in Thailand (Diptera: Culici- Entomol. Inst. (Ann Arbor) 24( 1): l-240. 96 MOSQUITO SYSTEMATICS VOL. 26, No. 2

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