92 Transactions of the Royal Canadian Institute 



Aedes (Heteronycha) diantaeus Howard, Dyar & Knab. 



Aides diantaeus Howard, Dyar & Knab, Mosq. No. & Cent. Am. & W. I., 

 iv. 758, 1917. 



A medium sized blajck mosquito. Mesonotum yellow, the two median 

 blackish lines distinct, narrow, sometimes joined into a single median 

 stripe; side stripes generally weak. Abdomen black, the white bands 

 obsolete dorsally, forming triangular spots at the sides at the bases of 

 the segments; venter whitish, the segments black at their apices. Legs 

 deep black, the femora white below, broadly so at base. Wing-scales 

 narrow, all dark. 



Liable to be confused with the normal form of lazarensis, from which 

 there is no marked distinction. The form of diantaeus with single dark 

 stripe closely resembles the normal form of punctor; but is more slender, 

 the legs blacker. Male genitalia always diagnostic. 



The winter is passed in the egg state. Larvae in early ground-pools 

 especially cold pools in spruce bogs; but in one river valley breeding in 

 flood-pools in summer. 



The m'^ales do not swarm, but attack the females singly as these are 

 tempting to bite some warm-blooded andmal. 



Distribution: Northern forests from Atlantic to Pacific. 



C^Ni^Dij^N Records. 

 White River, Ontario, June 17, 1918 (H. G. Dyar). 

 Terrace, British Cplumbia, August 13, 19 19 (H. G. Dyar). 

 Salvus, British Cloumbia, June 9, 19 19 (H. G. Dyar). 



Group HiRSUTERON. 



Aedes (Heteronycha) spencerii Theobald. 

 Culex spencerii Theobald, Mon. Clilic, ii, 99, 1901. 



A rather^ small, dark gray mosquito, inhabiting the open prairie. 

 Mesonotum dark brown in the middle, a grayish stripe on each side on 

 the margin and over antescutellar space. Abdomen with diffuse grayish 

 white bands at bases and apices of segments, and a line of the same 

 colour down the middle, cutting the black ground into paired squarish 

 spots; venter whitish. Legs black and grayish white, the latter colour 

 predominating beneath; femora white below. Wings with the costa, 

 first, third and fifth veins black-scaled, the alternating ones white-scaled. 



The winter is passed in the egg stage, the larvae developing in early 

 spring pools. The adults inhabit the open prairie, avoiding timber. 

 The males swarm after sunset over prominent objects on the prairie. 



Distribution: Prairies of central Canada and northern edge of the 

 United States. 



