68 PROCEEDINGS OF THE NATIONAL MUSEUM. VoL. 62. 
The larvae hatch long before the snow is all melted. They oc- 
cur in what become large open pools in ground hollows along the 
heads of mountain valleys. When the ground is still several feet 
deep in snow on the general level, these pools will be seen as wet 
places, perhaps open at one end and containing numerous well- 
grown larvae, crowding to the opening. After the snow is gone, 
the larvae and pupae remain for some days, drifting about in masses 
in the open pools, blown by the wind. The species occur only in 
the high mountains where suitable conditions occur, and though 
locally abundant, is incapable of general distribution, and generally 
annoys no one. It is to be considered as a local race of lazarensis, 
in male genitalia and larval habits the nearest to the European 
communis of any American form. 
Distribution.—Mountains of California. 
United States Records. 
CaLirorNIA: Yosemite Valley, Mariposa County, May, 1907 (D. J. Fullaway). 
Fallen Leaf Lake, El Dorado County, June 24, 1916 (H. G. Dyar). 
Lake Tahoe, Placer County, June 22, 1920 (H. G. Dyar). 
Summit, Placer County, June 15, 1920 (H. G. Dyar). 
Gold Lake, Sierra County, June 26, 1920 (H. G. Dyar). 
Bear Lake, Plumas County, June 24, 1920 (H. G. Dyar). 
AEDES (HETERONYCHA) PIONIPS Dyar. 
Aédes pionips Dyar, Ins. Ins. Mens., vol. 7, p. 19, 1919. 
_A large blackish mosquito. Mesonotum yellow, clear and even, 
rarely gray; two median black brown lines, broad and distinct and 
running far back; two short posterior lateral ones. Abdomen black, 
with basal segmental white bands, narrowed in the middle; venter 
whitish scaled, with more or less black at the apices of the segments. 
Legs black, femora white below; knee spots white. Wing scales 
all black. 
The coloration is not variable as far as observed; but the species 
is liable to be confused with large specimens of lazarensis. The 
winter is passed in the egg state, the larvae developing in early pools 
in spruce forests. The species is found only in the deepest forest 
or in northern regions. The males swarm after sunset in openings 
in the forest. 
Distribution—Northern forests, presumably from Atlantic to 
Pacific, although no far eastern records are available, but not in the 
moist Pacific coast strip. 
United States Records. 
Montana: Lake McDonald, June 25, 1921 (H. G. Dyar). 
Two Medicine Lake, July 7, 8, 10, 1921 (H. G. Dyar). 
AuLAsKA: Skagway, June 29, 1919 (H. G. Dyar). 
