pp. Last vein of the wings wholly black scaled.

q. Widely distributed north and south ([fig. 130]), (= maculipennis). A. quadrimaculatus*

qq. Distributed from Rocky Mountains westward. A. occidentalis

kk. Scutellum distinctly trilobed.

l. Cell R2 less than half as long as its petiole; thorax with metallic blue scales; median lobe of the scutellum not tuberculate; few small species which are not common. Uranotænia Arrib.

ll. Cell R2 nearly or quite as long as its petiole, or otherwise distinct.

m. Femora with erect outstanding scales; occiput broad and exposed. Large species. P. ciliata. P. howardi. Psorophora R. D.

mm. Femora without erect scales.

n. Clypeus bearing several scales or hairs, scutellum with broad scales only; back of head with broad scales; scales along the sides of the mesonotum narrow; some or the claws toothed; thorax marked with a pair of silvery scaled curved stripes; legs black with white bands at the bases of some of the segments ([fig. 134]). Yellow Fever mosquito Aedes (= Stegomyia) calopus.

nn. With another combination of characters. Numerous species of mosquitoes belonging to several closely related genera, widely distributed over the country. (Culex, Aedes, Ochlerotatus, etc.). Culex in the wide sense.