Key to the subfamilies and genera of mosquitoes (adult females) in Saudi Arabia (with subgenera and species for genera with only one species in the country)

1 Scutellum evenly rounded with setae evenly distributed along border; maxillary palpus of females with 5 palpomeres and about as long as proboscis; radial sector (vein R s) with basal spur (subfamily Anophelinae)...................... Anopheles

– Scutellum trilobed with setae in 3 distinct groups; maxillary palpus of females with fewer than 5 palpomeres and distinctly shorter than proboscis; vein R s without basal spur (subfamily Culicinae)........................................ 2

2(1) Anal vein (1A) reaches wing margin at about level of fork of cubital vein (Cu); cell R 2 (anterior forked cell of radius) shorter than 0.5 length of radius-two-plus-three (R 2+3) (petiole or stem); wing membrane apparently without microtrichia, these visible only under high magnification; proboscis somewhat swollen apically.......... Uranotaenia (Pseudoficalbia) unguiculata

– Anal vein reaches wing margin well beyond fork of Cu; cell R 2 more than 0.5 length of vein R 2+3; wing microtrichia visible under low magnification; proboscis not swollen apically...................................................... 3

3(2) Prespiracular setae present; wing with setae present ventrally at base of subcosta (Sc)......................... Culiseta

‒ Prespiracular setae absent; wing without setae ventrally at base of Sc............................................ 4

4(3) Postspiracular setae present............................................................................. 5

– Postspiracular setae absent............................................................................. 6

5(4) Wing scales nearly all very broad and asymmetrical; ungues (claws) of foreleg simple; abdominal tergum VIII with a row of teeth (comb); abdomen rounded and blunt apically; cerci short, hardly visible....... Mansonia (Mansonioides) uniformis

– Wing scales mostly narrow, if broad then not conspicuously asymmetrical; ungues of foreleg toothed; abdominal tergum VIII without a row of teeth; abdomen generally pointed apically and cerci long (except subgenus Stegomyia)............ Aedes

6(4) Femora and tibiae each with an anterior row of well-marked pale spots; normally 4 or more (3–10) lower mesepimeral setae present; prealar scales present..................................................... Lutzia (Metalutzia) tigripes

– Femora and tibiae without anterior rows of pale spots; normally one lower mesepimeral seta present or none, exceptionally 2–4; prealar scales present or absent, normally no prealar scales if 3 or 4 lower mesepimeral setae present.............. Culex