206 American Midland Naturalist Monograph No. 3 



depressions containing vegetable matter. They develop from overwintering eggs, 

 and there is but a single brood annually. Observations made by Rees (142) 

 in Utah indicate that the eggs will remain viable for at least three seasons and 

 probably longer in the absence of flooding. Similar observations have been 

 made elsewhere by Twinn (181) and Dyar (54). Adults have been collected 

 from February to August in the South but are more common from April to 

 June farther north (4th Sv. C. Med. Lab. records, 1942-1944, unpublished) . 



Aedes (Ochlerotatus) stimulans (Walker) 



Culex slimiilans Walker, 1848, List. Dipt. Brit. Mus., 1:4. 



adult female. — Medium sized species. Head: Proboscis long, dark, in- 

 conspicuously speckled with pale scales; palpi short, dark, speckled with pale 

 scales. Occiput dorsally with a median triangular patch of pale yellow lanceolate 

 scales, the patch broad posteriorly, narrowed anteriorly and projecting forward 

 between the eyes; scales of the submedian area adjacent to the margin of the 

 eye narrow, golden-brown; lateral region of occiput clothed with broad 

 appressed yellowish-white scales surrounding a small dark-scaled patch. Erect 

 forked scales numerous, those on central portion of occiput pale. Thorax: In- 

 tegument of scutum dark brown, covered with narrow bronzy-brown scales, 

 except for anterior and lateral margins, prescutellar space, and a pair of sub- 

 median longitudinal lines, all of which are pale yellow to whitish scaled. Dorsal 

 half of posterior pronotum with golden-brown lanceolate scales. Abdomen: 

 First tergite white scaled; remaining tergites each with a broad basal band of 

 white to pale-yellow scales; apical half of each tergite dark scaled, frequently 

 speckled with a few pale scales; apices of terminal segments pale scaled. Venter 

 primarily white scaled, frequently spotted with dark. Legs: Femora, tibiae, and 

 first segment of tarsi clothed with intermixed dark and pale scales, the pale 

 scales usually predominating on the femora; pale knee spots present. Segments 

 of hind tarsus each with a broad basal white ring; segments 1 to 4 of fore- and 

 mid-tarsi with narrower basal white rings than hind tarsus; segment 5 of fore- 

 and mid-tarsi usually entirely dark. Wing: Scales narrow, ligulate, intermixed 

 dark and dingy-white. 



ADULT male. — Coloration similar to that of female, terminalia (Fig. 

 11 IB). Lobes of ninth tergite (IXT-L) about as long as broad, separated by 

 the width of one lobe, each bearing several short spine-like setae. Tenth sternite 

 (X-S) prominent, heavily sclerotized beyond middle. Phallosome (Ph) sub- 

 cylindrical (a little narrower across apical third than across base), about twice 

 as long as basal width, open ventrally, closed dorsally, and with a notch at 

 apex. Claspette stem (Cl-S) pilose, slender, curved, extending beyond basal 

 lobe; claspette ^lament (CI-F) about as long as stem or slightly longer, broad, 

 blade-like (the blade very thin, broadest and angulate near middle of filament) , 

 gradually tapering to a pointed curved tip. Basis tyle (Bs) cylindrical, about 

 three and one-half times as long as width across middle, rounded at apex, 

 clothed with setae and scales on outer aspect and numerous long setae near 

 inner ventral margin; basal lobe (B-L) short, bluntly conical, with numerous 

 small apical setae and a stout curved, subapical spine; apical lobe (A-L) a prom- 



