12 INSECUTOR INSCITI^ MENSTRUUS 



northward into British Columbia would be very useful in con- 

 nection with this problem. 



The breeding places of taho'ensis are peculiar : Closed pools 

 without inlet or outlet, filled by melting snow, which usually be- 

 come completely dry by the first of July. These pools are due 

 to irregularities in the surface of the ground, where the ground 

 is compact enough to hold snow-water for a few weeks. They 

 have no connection with stream or lakes, though naturally com- 

 moner in valleys. They are not marshy, but have firm margins, 

 the water being held as in a bowl. The water is clear and cold, 

 but must be of a comparatively rich nature from its enclosed 

 state. These pools can often be recognized when dry. In 

 August, 1915, I visited Fallen Leaf Lake and located such a 

 hollow. In April, 1916, as expected, I found it full of water 

 with numerous pupae of taho'ensis. This is the only species that 

 I have found in these pools and they are always present in large 

 numbers, making taho'ensis the commonest mosquito of the 

 mountains while it lasts. Pullatus has the same habit, I believe ; 

 but it is now 14 years since I observed pullatus, and my recol- 

 lection is not as perfect as in the case of taho'ensis. There is 

 no species found in the east corresponding to pullatus or ta- 

 ho'ensis. 



Specimens before me referable to taho'ensis have been taken 

 as follows: Yosemite Valley, CaHfornia, May 19, 1907 (D. 

 J. Fullaway), May 14 to 19, 1916 (H. G. Dyar) ; Little Yose- 

 mite Valley, California, May 18, 193 6 (H. G. Dyar); Fallen 

 Leaf Lake, Lake Tahoe, California, May 27 to June 24, 1910 

 (H. G. Dyar); Lily Lake, Lake Tahoe, California, June Ifi, 

 191 n (H. G. Dyar) ; Tallac, Lake Tahoe, California, June 17, 

 1910 (H. G. Dyar); Tahoe Tavern, Lake Tahoe, California, 

 June 20, 1915 (A. K. Fisher); Summit, Placer County, Cali- 

 fornia, July 3 to 7, 1916, July' 19, 1915 (H. G. Dyar) ; Gold 

 Lake Camp, Plumas County, California, July 19 to 22, 1916 

 (H. G. Dyar) ; Gold Lake, Sierra County, California, July 20, 

 1916 (H. G. Dyar); Crater Lake, Oregon, August 16. 1916 

 (H. G. Dyar). 



Certain specimens of taho'ensis from Gold Lake develop a 



