io8 Transactions of the Royal Canadian Institute 



Aedes (Heteronycha) riparius Dyar & Knab. 



Aedes riparius Dyar & KJnab, Journ. N.Y. Ent. Soc, xv, 213, 1907. 



A large yellowish mosquito. Mesonotum dark yellow on the sides, 

 a broad brown band in the middle, contiguous to faint short posterior 

 lateral stripes, the mesonotum more or less oversoread with brown. 

 Abdomen blackish, with yellowish diffuse basal segmental bands and 

 scattering pale scales; venter yellowish, with black scales intermixed. 

 Legs mostly yellow scaled, the tarsi black, with basal white rings on the 

 joints, those on the hind legs large. Wiings with the scales dark, many 

 yellowish ones intermixed. 



The larva is unknown, and the habits of the males have not been 

 observed. The adults occur in wooded prairie, but are so much like 

 Hetcheri as to be indistinguishable without males. The species requires 

 further study, although evidently distinct. 



Distribution: Canadian prairies, probably coextensive with fietcheri 

 but has not been differentiated. 



Canadian Records. 

 Winnipeg, Manitoba, June 21, 1907 (F. Knab). 



Aedes (Heteronycha) excrucians Walker. 



Culex excrucians Walker, Ins. Saund., 429, 1856. 

 Culex ahfitchii Felt, Bull. 79, N.Y. State Mus., 381, 1904. 

 Culex siphonalis Grossbeck, Can. Ent., xxxvi, 332, 1904. 

 Aedes sansoni Dyar & Knab, Can. Ent., xli, 102, 1909. 

 Aedes euedes Howard, Dyar & Knab, Mosq. No. & Cent. Am. & W.I., iv, 

 714, 1917. 



A rather large brown mosquito with ringed legs. Mesonotum 

 yellowish gray on the sides, a broad reddish brown or dark brown band 

 in the middle, joining the short posterior stripes. Abdomen blackish, 

 with basal segmental white bands, widening on the sides, and some white 

 scales on the apices of the segments also; venter whitish, with a row of 

 black dashes on middle line. Legs black, with many white scales inter- 

 mixed on femora and tibiae, the tarsi with white rings at the bases of 

 the joints, broad on the hind pair. Wings with black scales, with more 

 or less white ones intermixed, especially along costal region. 



The adult females are not certainly distinguishable from fitchii or 

 stimulans. This is commonly a larger species than fitchii, the sides of 

 the mesonotum more shaded with brown, often completely so. The wing 

 scales commonly have few or no white scales; but all the characters are 

 intergradient, and not of diagnostic value. The larvae and male geni- 

 talia differ conspicuously in the three species. 



