106 INSECUTOR INSCITI^ MENSTRUUS 



observed to be able to take advantage of these, by breeding 

 successfully in pools produced by irrigation. While originally 

 these forms were doubtless confined to a single annual genera- 

 tion following the spring snows, now they breed as often as 

 the obliging farmers furnish suitable pools. These species are : 

 A'cdes curriei, nigromaculis, vexans, trivittatus and another 

 referred to under spencerii below. 



The river valleys furnish two faunal areas, one the river 

 bottom itself, wooded, often densely clothed with cottonwood 

 and willow; the other the high flood-plain, destitute of trees 

 and resembling a prairie. Characteristic of the latter region 

 are Aides curriei, nigromaculis, and idahoensis. A. vexans 

 also invades it, though commoner in the river bottom. The 

 habits of trivittatus are probably similar to those of vexans, 

 although being a rarer species, specimens were captured only 

 by the river, though bred from prairie pools. The males of 

 curriei, nigromaculis, and idahoensis swarm on the prairie; 

 vexans only by the river ; the swarming of trivittatus was not 

 observed. 



Exclusively river-bottom species are : A'edes aldrichi, cine- 

 reus, and sansoni. A'edes campestris and fletcherl. listed by 

 Parker, were not taken by me. Parker does not indicate the 

 localities where he found them. Both are prairie species. 



THE LOCALITIES 



(1) Evaro, 3,971 feet. In spite of the comparatively low 

 elevation, this has much the character of a mountain meadow, 

 a typical breeding place for the early snow-water species. A 

 flat marshy area, draining in both directions, is surrounded by 

 hills clothed with pine forest. When visited, the season was 

 far advanced ; not only had all breeding of the early species 

 ceased, to be replaced by larvae of Culex and Culiseta, but the 

 mosquitoes themselves were nearly gone. Only seven speci- 

 mens were found in a day's collection, though earlier they must 

 have been numerous, as was stated to have been the case by the 

 station agent. 



A'edes idaho'ensis Theobald. One female. 



A'edes sansoni Dyar & Knab. Two females. Not certainly 



