Culex, Linnaeus (Harbach, 2023

Dawah, Hassan A., Abdullah, Mohammed A., Ahmad, Syed Kamran, Turner, James & Azari-Hamidian, Shahyad, 2023, An overview of the mosquitoes of Saudi Arabia (Diptera: Culicidae), with updated keys to the adult females, Zootaxa 5394 (1), pp. 1-76 : 55-57

Key to the subgenera and species (adult females) of Culex in Saudi Arabia

1 Proboscis shorter than forefemur; hindtarsomere 1 shorter than hindtibia, not longer than 0.85 length of hindtibia; abdominal terga entirely dark-scaled (subgenus Barraudius )..................................................... pusillus

– Proboscis longer than forefemur; hindtarsomere 1 usually as long as or longer than hindtibia or only slightly shorter, not shorter than 0.85 length of hindtibia; abdominal terga with pale bands at least on some segments............................ 2

2(1) Abdominal terga with apical pale bands or apicolateral pale patches............................................. 3

– Abdominal terga with basal pale bands or basolateral pale patches (subgenus Culex )............................... 6

3(2) Decumbent scales of vertex mainly narrow and dark, those on ocular line broad and pale; scutal scales entirely dark and very fine (subgenus Culiciomyia )................................................................... nebulosus

– All decumbent scales of vertex narrow and pale; scutal scales predominantly pale and rather coarse................... 4

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) terminates distal to mediocubital (mcu) crossvein; lower mesepimeral seta absent (subgenus Oculeomyia )............................................................................................... 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 pale scales; tarsi without pale rings; proboscis without pair of pale spots at apex before labella; last palpomere without pale scales; central part of ocular line with broad scales; 1A terminates before crossvein mcu; lower mesepimeral seta present (subgenus Maillotia )............................. 5

5(4) Pale bands of abdominal terga complete, more or less even width; postspiracular scales present................. arbieeni

– Pale bands of abdominal terga narrow or incomplete, sometimes reduced to small apicolateral patches; postspiracular scales absent................................................................................... salisburiensis

6(2) One or more lower mesepimeral setae present (note presence of alveoli if setae are missing); proboscis and tarsi without pale rings (except in Cx. duttoni )............................................................................ 7

– No lower mesepimeral setae (note absence of alveoli); proboscis with median pale ring; tarsi with narrow pale rings (Sitiens Group)............................................................................................. 8

7(6) Tarsi with narrow pale rings; usually 2‒4 lower mesepimeral setae present (Duttoni Group).................... duttoni

– Tarsi without pale rings; usually 1, rarely 2, lower mesepimeral setae present (except in Cx. laticinctus ) (Pipiens Group)... .................................................................................................. 10

8(6) Wing with 3 conspicuous pale areas on costa (C) and pale markings on other veins; midtibia with anterior pale stripe.................................................................................................. mimeticus

– Wing without pale areas, occasionally with scattered pale scales; midtibia without anterior pale stripe.................. 9

9(8) Anterior surface of fore- and midfemura speckled with pale scales; scutum with indefinite mottled pattern; cell M 2 (posterior forked cell of media) long, furcation of radius-two-plus-three (R 2+3) (petiole or stem) distal to furcation of media (M); scutal integument dark................................................................................. sitiens

– Anterior surface of fore- and midfemura not speckled; scutum without mottled pattern; furcation of R 2+3 proximal to furcation of M; scutal integument pale brown........................................................ tritaeniorhynchus

10(7) Postspiracular scales present........................................................................... 11

– Postspiracular scales absent............................................................................ 15

11(10) All tibiae with anterior pale stripe; prealar and upper and lower mesokatepisternal scale-patches confluent; basal pale bands of abdominal terga usually produced posteromedially into triangular patches................................... theileri

– Fore- and midtibiae normally without anterior pale stripe ( Cx. univittatus and Cx. perexiguus usually have an anterodorsal pale stripe on midtibia); prealar and upper and lower mesokatepisternal scale-patches separate, not confluent; basal pale bands of abdominal terga more or less of even length, not produced posteriorly.......................................... 12

12(11) Hindtibia with anterior pale stripe; wing with pale scales at base of costa (C)..................................... 13

– Hindtibia without anterior pale stripe; wing entirely dark-scaled............................................... 14

13(12) Anterior surface of midfemur dark-scaled or with incomplete narrow pale stripe; wing seldom with few scales on anal vein 2A....................................................................................... perexiguus

– Anterior surface of midfemur with complete narrow pale stripe; wing usually with row of scales on anal vein 2A..................................................................................................... univittatus

14(12) Hindfemur with anterodorsal dark stripe on distal 0.5 or less; abdominal sterna usually entirely pale-scaled; scales of forecoxa usually all pale................................................................................ sinaiticus

– Hindfemur with complete or nearly complete anterodorsal dark stripe; abdominal sterna with apical dark bands; forecoxa with some dark scales.............................................................................. simpsoni

15(10) Abdominal sterna with apical dark bands; scutal scales with distinct reddish tint.............................. decens

– Abdominal sterna unbanded, dark scales confined to midline and/or posterolateral corners when present; colour of scutal scales variable........................................................................................... 16

16(15) Scales of forecoxa mostly pale; wing with short line of pale scales at base of costa (C); proboscis all dark or faintly pale beneath............................................................................................ 17

– Forecoxa with some dark scales; wing entirely dark-scaled; proboscis usually distinctly pale beneath in middle......... 18

17(16) Hindfemur with distal 0.2–0.3 of anterior surface dark-scaled; 2‒4 lower mesepimeral setae present; thoracic integument pale; scutal scales light yellowish brown; scutum with short diagonal line of whitish scales along prescutal suture..... laticinctus

– Hindfemur with distal 0.3–0.4 of anterior surface dark-scaled; 1 lower mesepimeral seta present; thoracic integument darker; scutal scales darker; scutum with curved line of pale scales along prescutal suture and posterior dorsocentral setae.................................................................................................... mattinglyi

18(16) Scutal scales more or less buff-coloured; 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 (R 2+3) (petiole or stem)................................................. 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 R 2+3 ................................................................................. pipiens (including form molestus )