Key to subgenera and species of genus Culex: adults

(key characters are illustrated in Figs 1–4)

1. Proboscis shorter than forefemur; hindtarsomere 1 shorter than hindtibia, not more than 0.85 length of hindtibia; abdominal terga entirely dark-scaled [in males, maxillary palpus generally with short spinelike setae] (subgenus Barraudius)............................................................................................................................................................... 2

- Proboscis longer than forefemur; hindtarsomere 1 usually as long or longer than hindtibia or only slightly shorter, not less than 0.85 length of hindtibia; abdominal terga with pale bands at least on some segments, except Cx. (Cux.) antennatus ...................................................................................................................................................... 3

2(1). Abdominal terga with lateral pale scales more or less developed as spots; postspiracular scales absent ................. ................................................................................................................................................................ Cx. pusillus

- Abdominal terga with pale scales arranged in more or less distinct stripes, sometimes forming triangular spots on anterior margins of terga; postspiracular scales present ..................................................... Cx. modestus (Note 31)

3(1). Abdominal terga with apical pale bands or apicolateral pale patches [lower mesepimeral setae present except in subgenus Oculeomyia] ............................................................................................................................................. 4

- Abdominal terga with basal pale bands or basolateral pale patches (except Cx. antennatus, which has lateral pale patches on terga VI and VII) [lower mesepimeral setae present in Pipiens Group; absent in Sitiens Group] (subgenus Culex) ................................................................................................................................................................. 9

4(3). Wing speckled with dark and pale scales, many scales broad ovate; proboscis with ring of pale scales; basal dark area of terga speckled with pale scales; femora and tibiae heavily speckled; tarsi with pale rings; proboscis with pair of dorsolateral pale spots at apex before labella; last palpomere with some pale scales; central part of ocular (orbital) line without scales; anal vein (1A) (vein 6) terminates distal to mediocubital (mcu) crossvein; in males,

proboscis with ventral cluster of setae at false joint; lower mesepimeral seta absent (subgenus Oculeomyia) (Note 32) ........................................................................................................................................... Cx. bitaeniorhynchus – Wing uniformly dark-scaled, scales narrow clavate; proboscis without ring of pale scales; basal dark area of terga not speckled; femora and tibia not speckled, may have a few pale scales or a row of scales; tarsi without pale rings; proboscis without pair of pale spots at apex before labella; last palpomere without pale scales; central part of ocular (orbital) line with broad scales; 1A terminates before crossvein mcu; in males, proboscis without ventral cluster of setae at false joint; lower mesepimeral seta present ................................................................................ 5

5(4). Prealar and postspiracular scales absent; pale areas of terga clearly reduced, medially narrowed or interrupted; maxillary palpus dark; end of subcosta (Sc) distinctly proximal to furcation of radius-two-plus-three (R2+3) (petiole or stem) and media (M) (vein 4) (subgenus Neoculex) ....................................................................................... 6

- Prealar and usually postspiracular scales present; terga with broad pale areas of even width or medially extended posteriorly; palpomere 2 usually with pale scales; end of Sc nearly aligned with furcation of R2+3 and M or slightly proximal to them (subgenus Maillotia) ................................................................................................................... 7

6(5). Apical pale bands of abdominal terga narrow, not interrupted, sometimes represented only by a line of pale scales along border of tergum; in males, last abdominal segment not usually very setose.............................. Cx. territans

- Apical pale bands interrupted at least on some terga, always broader at sides; in males, last abdominal segments with numerous, long setae ................................................................................................ Cx. impudicus * (Note 33)

7(5). Sterna entirely pale-scaled; in males, last palpomere with many setae [pale bands of most abdominal terga with projection].......................................................................................................................................... Cx. deserticola

- Sterna dark with large triangular pale areas at apex of most sterna; in males, last palpomere devoid or nearly devoid of setae .......................................................................................................................................................... 8

8(7). Pale bands of most abdominal terga with projection; upper proepisternal area with many prominent scales; relatively darker species; palpomere 2 usually with prominent pale scales on dark background; in males, gonocoxite of genitalia with unusually broad, sclerotized, flattened process at apex............................ Cx. hortensis (Note 34)

- Pale bands of abdominal terga of more or less even width, at most a few terga with weak projection; upper proepisternal area with fewer prominent scales; paler species; palpomere 2 with pale scales less prominent; in males, gonocoxite of genitalia otherwise .............................................................................................. Cx. arbieeni

9(3). Proboscis with pale ring in middle; lower mesepimeral setae absent; tarsi with narrow pale rings ( Sitiens Group). ................................................................................................................................................................................ 10

- Proboscis without pale ring; lower mesepimeral setae present; tarsi without pale rings ( Pipiens Group)............. 14

10(9). Wing with 3 conspicuous pale areas on costa (C) and pale markings on other veins; midtibia with anterior pale stripe.................................................................................................................................................... Cx. mimeticus

- Wing without pale areas, occasionally with scattered pale scales; midtibia without anterior pale stripe ............. 11

11(10).Anterior surface of fore- and midfemur speckled with pale scales; scutum with indefinite mottled pattern; cell M2 (posterior forked cell of vein 4) long, furcation of radius-two-plus-three (R2+3) (petiole or stem) distal to furcation of media (M) (vein 4); scutal integument dark ......................................................................................... Cx. sitiens

- Anterior surface of fore- and midfemur not speckled; scutum without mottled pattern; furcation of R2+3 proximal to furcation of M; scutal integument pale brown ( Vishnui Subgroup) (Note 35)................................................... 12

12(11).Pale ring of proboscis usually with proximal extension on ventral surface; hindfemur pale with an apical dark ring; erect scales on vertex all dark, dirty yellow to brown in middle; cell R2 (anterior forked cell of vein 2) more than 3.0 length of radius-two-plus-three (R2+3) (petiole or stem); in males, proboscis with ventral cluster of 10 or more setae at false joint ......................................................................................................... Cx. tritaeniorhynchus

- Pale ring of proboscis without proximal extension on ventral surface; hindfemur with dark and pale areas, with or without speckling, without apical dark ring; vertex with mixture of pale (cream, pale yellow, or beige) and dark erect scales, rarely all dark; cell R2 less than 3.0 length of R2+3; in males, proboscis with at most 10 (usually fewer) setae at false joint.................................................................................................................................................... 13

13(12).Anterior surface of hindfemur with pale stripe contrasting well with dark-scaled area; in males, proboscis usually without ventral cluster of setae at false joint, 1 or 2 setae sometimes present ............................ Cx. pseudovishnui

- Anterior surface of hindfemur with pale stripe not distinctly contrasting with dark-scaled area; in males, proboscis with ventral cluster of 5–10 setae at false joint ................................................................................... Cx. vishnui *

14(9). At least forefemur with pale stripe on anterior surface, stripe usually present on fore- and midfemur and all tibiae ................................................................................................................................................................................ 15

- Fore- and midfemur without anterior pale stripe ( Cx. univittatus and Cx. perexiguus usually have an anterodorsal pale stripe on midtibia) ........................................................................................................................................... 16

15(14).Basal pale bands of abdominal terga usually produced posteromedially into triangular patches; prealar and postspiracular scales present; hindfemur with a dark ventral stripe in apical third; prealar and upper and lower mesokatepisternal scale-patches confluent ............................................................................................. Cx. theileri

- Basal pale bands of abdominal terga more or less of even width, not produced posteriorly; prealar and

postspiracular scales absent; ventral surface of hindfemur completely pale-scaled; prealar and upper and lower mesokatepisternal scale-patches not confluent ..................................................................... Cx. vagans * (Note 36) 16(14).Postspiracular scales present; hindtibia with pale ring or well-developed and prominent pale spot at apex [prealar scales present] ......................................................................................................................................................... 17

- Postspiracular scales absent; hindtibia without pale ring or spot at apex (except Cx. laticinctus, which has a weak apical pale spot) [prealar scales present or absent] ................................................................................................ 19

17(16).Hindtibia without anterior pale stripe; wing entirely dark-scaled; basal pale bands of terga straight, 0.3–0.4 length of tergum, slightly produced laterally, especially on terga VI and VII; anterior surface of forecoxa pale-scaled or with a few dark scales in middle.......................................................................................................... Cx. sinaiticus

- Hindtibia with anterior pale stripe; wing with pale scales at base of costa (C); basal pale bands on terga narrower and convex; anterior surface of forecoxa with numerous dark scales in middle ................................................... 18

18(17).Anterior surface of midfemur dark-scaled or with incomplete narrow pale stripe; wing seldom with few scales on anal vein 2A ....................................................................................................................................... Cx. perexiguus

- Anterior surface of midfemur with complete narrow pale stripe; wing usually with row of scales on anal vein 2A ......................................................................................................................................... Cx. univittatus * (Note 37)

19(16).Abdominal terga unbanded, terga VI and VII with lateral pale stripes; in male, proboscis with ventral cluster of setae at false joint............................................................................................................................... Cx. antennatus

- Basal pale bands present on terga of most segments; in male, proboscis without ventral cluster of setae at false joint ........................................................................................................................................................................ 20

20(19).Basal pale bands of abdominal terga very broad, 0.50–0.67 length of segment, not narrowed toward sides; scales of forecoxa mostly pale; wing with short line of pale scales at base of costa (C); proboscis all dark or faintly pale beneath; 2–4 lower mesepimeral setae present; hindtibia with apical pale spot [prealar scales present or absent] ... ............................................................................................................................................................ Cx. laticinctus

- Basal pale bands of abdominal terga narrower, less than 0.5 length of segment, often narrower at sides, sometimes reduced to lateral spots or even absent from some terga; forecoxa with some dark scales; wing entirely darkscaled; proboscis usually distinctly pale beneath in middle; 1, rarely 2, lower mesepimeral setae present; hindtibia without apical pale spot (Note 38).......................................................................................................................... 21

21(20).Scutal scales more or less buff-colored; basal bands of abdominal terga nearly white, usually slightly paler than sternal scaling; tergal bands slightly if at all darker than basolateral white spots; subcosta (Sc) normally intersects costa (C) before furcation of radius-two-plus-three (R2+3) (petiole or stem) [prealar scales absent].......................... ................................................................................................................................................ Cx. quinquefasciatus

- Scutal scales golden brown with reddish tint; basal bands of abdominal terga yellowish, usually same colour as sternal scaling; tergal bands distinctly darker than basolateral white spots; Sc normally intersects C at or beyond furcation of R2+3 ...................................................................................................................................................... 22

22(21).Cell R2 (anterior forked cell of vein 2) more than 4.0 length of radius-two-plus-three (R2+3) (petiole or stem); integument and scales between supraalar and posterior dorsocentral setae usually noticeably darker than surrounding integument and scales, evident as pair of ovoid spots [prealar scales normally absent] ............................ ...................................................................................................................... Cx. pipiens (including form molestus)

- Cell R2 less than 4.0 length of R2+3; integument and scales between supraalar and posterior dorsocentral setae not appreciably darker than surrounding integument and scales [prealar area normally with 4 scales or more, occasionally absent] .................................................................................................................................. Cx. torrentium