INSEJCUTOR INSCITI^ MENSTRUUS 11 



1-5, 7, 8, 16-18, 1919 ; Tahkeena River, Yukon Territory, July 

 19, 1919; Byer's Camp, Yukon Territory, July 6, 1919; Big 

 Salmon, Yukon Territory, July 15, 1919 ; Carmack's, Yukon 

 Territory, July 14, 1919; Horse Falls, Yukon Territory, July 

 13, 1919; Knudson's Camp, Yukon Territory, July 6, 1919; 

 Tantalus Mine, Yukon Territory, July 6, 1919 ; Selkirk, Yukon 

 Territory, July 13, 1919 ; Dawson, Yukon Territory, July 

 7-11, 1919. 



Aedes intrudens Dyar. 



A'edes intrudens Dyar, Ins. Ins. Mens., vii, 23, 1919. 



This species occurred in early snow-pools and also in the 

 Skeena flood-pools, which are filled by seepage and do not hold 

 snow-water on account of the porosity of the ground. It was 

 thus encountered in houses as late as August, contrary to its 

 normal early habits. No differences were observed in these 

 late specimens from normal early ones, either in coloration or 

 habits. The species was not encountered in the Yukon water- 

 shed. 



Total, 116 specimens: Terrace, British Columbia, August 12, 

 13, 14, 1919; Salvus, British Columbia, June 3, 4, 7, 8, 9, 10, 

 1919 ; Kwinitsa, British Columbia, May 22-26, August 14, 1919. 



Aedes pullatus Coquillett. 



This species, which inhabits high altitudes in the Rocky 

 Mountains southward to Colorado, comes down to the valley 

 floor in the lower Skeena and the Yukon, and reaches sea- 

 level at Skagway, Alaska. 



The larvse are to be found late in the season in the last re- 

 maining pools, together with pionips. The species was rather 

 common at Dawson, my most northerly point, where males 

 were seen swarming over willow bushes on the hillside after 

 sunset, or even as early as 4 p. m. when the sun passed behind 

 a temporary cloud. 



Total, 643 specimens : Kwinitsa, British Columbia, May 29, 

 31, June 1, 2, 7, 1919; Skagway, Alaska, June 24-30, July 1-4, 

 6, 1919; Bennett, British Columbia, July 28, 1919; Atlin, 

 British Columbia, July 23, 24, 1919; Carcross, Yukon Terri- 



