Culex, Linnaeus, 1758

Simsaa, Mishkat A. A., Harbach, Ralph E., Ali Almalik, Alaa M., Ahmed, Elsheima M., Eisa, Alwia A., Mohamed, Asia H. & Azrag, Rasha S., 2021, Culex mosquitoes (Diptera: Culicidae) recorded along the Nile River in central and northern Sudan, with a key for the identification of all species of the genus known to occur in the country, Zootaxa 4963 (3), pp. 401-411 : 406-408

Key for the adults of Culex and Lutzia species known to occur in northern Sudan

1 Normally 4 or more lower mesepimeral setae; fore- and midfemora and -tibiae each with an anterior row of small pale spots............................................................................................ Lt. tigripes

- A single lower mesepimeral seta (exceptionally 2 or 3) or none; femora and tibiae without rows of pale spots (except Cx. poi- cilipes)............................................................................................. 2

2(1) Acrostichal setae absent.................................................................. Cx. (Cui.) macfiei

- Acrostichal setae present, may be quite small............................................................... 3

3(2) No lower mesepimeral seta; proboscis and tarsi with pale rings................................................. 4

- 1–3 lower mesepimeral setae............................................................................ 8

4(3) Femora and tibiae with rows of small pale spots anteriorly.................................... Cx. (Ocu.) poicilipes

- Femora and tibiae without pale spots..................................................................... 5

5(4) Abdominal terga with apical pale bands; wing with numerous scattered pale scales; proboscis with a pair of dorsolateral pale spots before the labella........................................................... Cx. (Ocu.) bitaeniorhynchus

- Abdominal terga without apical pale bands; wing with few or no pale scales; proboscis dark at the apex (but the labella may be pale)............................................................................................... 6

6(5) Thorax brownish or scutum with many pale scales; scutum usually with anterior 0.5 mainly pale-scaled; wing without pale scales at the apex, length 4.0– 6.5 mm; abdominal terga with basomedian and apicolateral triangular patches of pale scales...................................................................................... Cx. (Ocu.) annulioris

- Scutal scales form an indefinite mottled pattern, or scales all dark; wing length 2.0–4.0 mm.......................... 7

7(6) Femora with numerous scattered pale scales anteriorly; cell R 2 of wing short, its base distal to the base of cell M 1; pale scales of the proboscis confined to a distinct median ring................................................ Cx. (Cux.) sitiens

- Femora without or with a few scattered pale scales; cell R 2 longer, its base at least slightly proximal to the base of M 1; pale scaling of the proboscis in a ring with a proximal extension on the ventral surface............ Cx. (Cux.) tritaeniorhynchus

8(3) Abdominal terga with basal pale bands (except Cx. argenteopunctatus subsp. kingii and some Cx. neavei ) or lateral pale spots; vertex and ocular line of the head with narrow decumbent scales................................................ 9

- Abdominal terga completely dark-scaled or with apical pale scaling............................................ 24

9(8) Tarsi, especially hindtarsi, with narrow pale rings; prealar scales absent; midtibia with a pale anterior stripe; postspiracular scales usually present.................................................................... Cx. (Cux.) duttoni

- Tarsi entirely dark-scaled; midtibia with or without an anterior pale stripe; postspiracular scales usually absent.......... 10

10(9) Femora of fore- and midlegs and tibiae of all legs with anterior pale stripes running the whole length; hindtibia without a dorsal pale spot at the apex; prealar and upper and lower mesokatepisternal scale-patches contiguous, forming a single patch............................................................................................ Cx. (Cux.) theileri

- Femora and tibiae either without anterior stripes or if stripes are present on any of them then hindtibia with a dorsal pale spot at the apex; prealar and upper and lower mesokatepisternal scale-patches not continuous, in 3 separate patches.......... 11

11(10) Scutum with 4 spots of silvery-white scales; small dark species, abdominal terga without pale bands...................................................................................... Cx. (Cux.) argenteopunctatus subsp. kingii

- Scutum without silvery-white spots..................................................................... 12

12(11) Postspiracular and prealar scales present; hindfemur with anterior surface mainly white-scaled, at most distal 0.2 dark-scaled .................................................................................................. 13

- Postspiracular scales absent; prealar scales normally present.................................................. 17

13(12) Hindtibia with distinct or indistinct anterior and posterior pale stripes; wing with or without a short line of pale scales at the base of the costa......................................................................................... 14

- Hindtibia without an anterior pale stripe, apex with a conspicuous white spot; wing entirely dark-scaled............... 16

14(13) Anterior surface of midfemur with distinct or indistinct anterior pale stripe; hindtibia with distinct anterior and posterior pale stripes on proximal 0.8, with distinct apical pale spot; costa of wing with a short line of pale scales at the base; patch of scales covers more or less of the dorsal 0.5 of the postspiracular area; pale bands of abdominal terga with normal basal pale bands.. .................................................................................................. 15

- Anterior surface of midfemur normally without an anterior pale stripe, weakly indicated when present; hindtibia with rather indistinct anterior and posterior pale stripes ending before the base, with rather an indistinct apical pale spot; wing entirely darkscaled, without pale scales at the base of the costa; scales of postspiracular area tend to occur in a small patch near the spiracle; pale bands of the abdominal terga reduced or absent............................................. Cx. (Cux.) neavei

15(14) Proboscis with pale scales on middle of ventral surface; midfemur with a complete distinct or indistinct anterior pale stripe; anterior and posterior pale stripes of hindtibia separated ventrally by a complete dark stripe; wing vein 2A (posterior to vein 1A) of female usually with a line of scales................................................. Cx. (Cux.) univittatus

- Proboscis pale-scaled ventrally except at base, weakly on distal 0.25; midfemur with or without an incomplete faint or distinct anterior pale stripe; anterior and posterior pale stripe of hindtibia partly separated on proximal 0.5 or less by a weak ventral dark stripe; wing vein 2A of female occasionally with a few scales.................................. Cx. (Cux.) perexiguus

16(13) Hindfemur with complete or nearly complete anterodorsal dark stripe; females: abdominal sterna with apical dark bands; forecoxa with some dark scales; males: abdominal sterna mainly dark-scaled, with basolateral pale spots, maxillary palpus normal.................................................................................... Cx. (Cux.) simpsoni

- Hindfemur with an anterodorsal dark stripe on distal 0.5 or less; females: abdominal sterna usually entirely pale-scaled; scales of forecoxa usually all pale; males: abdominal sterna mainly pale-scaled, posterior sterna usually with dark scales posteriorly, maxillary palpus sparsely setose......................................................... Cx. (Cux.) sinaiticus

17(12) Abdominal terga with basal pale bands................................................................... 18

- Abdominal terga, at least the first few, without pale bands; mesepimeron with a distinct scale-patch in the middle....... 20

18(17) Thorax pale; proboscis entirely dark-scaled; abdominal sterna pale-scaled; 2–4 lower mesepimeral setae frequently present; hindtibia with conspicuous apical pale spot................................................ Cx. (Cux.) laticinctus

- Thorax darker; proboscis pale beneath in the middle; only 1 lower mesepimeral seta; hindtibia with inconspicuous apical pale spot............................................................................................... 19

19(18) Scutal scales golden brown with reddish tint; wing of female with cell M 2 more than 3 times as long as its stem (vein R 2+3), subcosta normally intersects the costa at or beyond the furcation of R 2+3; basal bands of abdominal terga yellowish, usually same color as the sternal scales; tergal bands of female distinctly darker than basolateral white spots........... Cx. (Cux.) pipiens

- Scutal scales more or less buff-colored; wing of female with cell R

2

2.8–3.3 times as long as vein R

2+3

, subcosta normally in- tersects the costa before the furcation of R 2+3; basal bands of abdominal terga nearly white, usually slightly paler than sternal scaling, tergal bands of female slightly if at all darker than basolateral white spots............. Cx. (Cux.) quinquefasciatus

20(17) Antenna of female normal, each flagellomere with 4–6 long setae; knob of halter usually dark-scaled.................. 21

- Antenna of female sub-verticillate; first few flagellomeres each with 10–20 long setae; halter entirely yellow-scaled...... 23

21(20) Small brown species; abdominal terga without basal pale bands, terga VI and VII with lateral pale stripes; sterna pale-scaled.................................................................................... Cx. (Cux.) antennatus

- Larger species; abdominal terga with or without narrow basal pale bands, with basolateral pale patches; sterna with apical dark bands............................................................................................. 22

22(21) Erect scales of head all or nearly all dark; scutum with evenly dispersed uniform reddish-brown scales, anterior and lateral margins and prescutellar area with pale scales; hindfemur with 0.2 or less of anterior surface dark-scaled; hindtibia with a pale spot at the apex.......................................................................... Cx. (Cux.) decens

- Erect scales of head all dark; scales on margins of scutum and prescutellar area creamy-white; hindfemur with anterior dark area at apex longer than broad; hindtibia entirely dark-scaled....................................... Cx. (Cux.) perfuscus

23(20) Proboscis dark-scaled; 2 lower mesepimeral setae; hindtibia with a spot of pale scales at the apex; abdominal sterna with dark apical bands.......................................................................... Cx. (Cux.) grahamii

- Proboscis pale beneath; usually only 1 lower mesepimeral seta; hindtibia entirely dark-scaled; abdominal sterna entirely palescaled or with only a few dark scales on the apical margins...................................... Cx. (Cux.) weschei

24(8) Vertex of head with narrow whitish decumbent scales; mesepimeron with very few or no scales....... Cx. (Eum.) kingianus

- Vertex with some moderately broad scales, at least on the ocular line........................................... 25

25(24) Only ocular line of head with broad scales, the scales white; abdominal terga with apical lateral pale spots or all dark; thoracic pleura gray-dusted................................................................................... 26

- Vertex of head usually with more numerous broad scales, and these usually dark.................................. 27

26(25) Small species; length of wing 3–4 mm; mesepimeron usually without distinct scale-patch; gonocoxite of male genitalia with few short setae........................................................................ Cx. (Cui.) nebulosus

- Larger species; length of wing 4–5 mm; mesepimeron usually with a large patch of scales; gonocoxite of male genitalia with dense patch of soft pale setae............................................................. Cx. (Cui.) cinereus

27(25) Dorsum of head almost entirely clothed in broad decumbent scales; legs mainly dark-scaled; hindfemur only indistinctly palescaled ventrally.................................................................. Cx. (Eum.) inconspicuosus

- Dorsum of head with a fairly broad band of decumbent scales in front adjoining the eyes; hindfemur more extensively palescaled, ventral surface distinctly paler................................................. Cx. (Eum.) simpliciforceps