20 INSECUTOR INSCITI^ MENSTRUUS 



Prince Rupert, British Columbia, May 13-June 13, July 8, 9, 

 1919; Ketchikan, Alaska, August 8, 1919; Cape Fanshaw, 

 Alaska, June 22, 1919 ; Skagway, Alaska, June 24, July 1, 2, 

 3, 27, 28, 30, 31, August 1-5, 1919; Taku, British Columbia, 

 July 22, 1919; Atlin, British Columbia, July 24-27, 1919; 

 Carcross, Yukon Territory, July 27, 1919; White Horse, 

 Yukon Territory, June 27-30, July 4, 1919; Dawson, Yukon 

 Territory, July 9, 14, 15, 16, 18, 1919. 



The species evidently ranges all down the Yukon. I have 

 specimens through the U. S. Biological Survey as follows: 

 Flat, Alaska, June 12, 1917 (A. H. Twitchell) ; Beaver Moun- 

 tains, Alaska, May 26, 1917 (A. H. Twitchell) ; Iditarod, 

 Alaska, June 12, 1918 (Alice Twitchell). 



Culiseta incidens Thomson. 



Throughout the Canadian and Coastal regions, preferring 

 artificial pools or barrels for oviposition. In the Yukon Val- 

 ley the black markings on the wings are commonly very much 

 reduced ; the species being with difficulty separated from 

 impatiens at casual glance. I give all the localities together. 



Total, 105 specimens: Hazelton, British Columbia, Septem- 

 ber 7-10, 1919; Prince Rupert, British Columbia, May 30- 

 June 9, 1919; Cape Fanshaw, Alaska, June 22, 1919 (the 

 specimen plainly seen, but escaped capture) ; Atlin, British 

 Columbia, July 22, 23, 24, 26, 27, 1919 ; White Horse, Yukon 

 Territory, June 28-30, July 1-4, 1919 ; Dawson, Yukon Terri- 

 tory, July 15, 16, 18, 19, 1919. 



Culiseta alaskaensis Ludlow. 



Not uncommon in the Yukon Valley. The species is ad- 

 dicted to grassy pools, such as occur along river-beds, not in 

 forest. It is absent from the forested Canadian region, but 

 follows the mountains from the Yukon southward onto the 

 Canadian plains. 



Total, 78 specimens: Edmonton, Alberta, April 27, 1919; 

 Atlin, British Columbia, July 25, 26, 1919; White Horse, 

 Yukon Territory, June 26-30, July 1-4, 16, 1919; Selkirk, 



