LIFE HISTORIES OF CULEX. 31 



the commonest species in this h)cality, sliow that only two 

 days are needed in favorable weather in Augnst ; perhaps, 

 a longer period is required in the cooler weather of spring 

 and fall. 



As the insect approaches the imago stage it needs more 

 air, and consequently remains altogether at the surface, 

 unless disturbed from above ; it drops quickly below and 

 rises atj-ain almost immediatelv. 



The newly formed pupa is usually nuich paler than 

 that of a few hours' existence, and its bulk also ajtpears 

 to increase slightly. When the period of emergence ai- 

 rives the abdominal segments are distended backwards on 

 the surface, and the pupa cracks through the middle of 

 the cephalothoracic region. Now the imago may be ^ecn 

 to rapidly extricate itself, using its long hind legs to i)ush 

 with, and balancing itself with the anterior and middle 

 pairs. Though it can stand for ten or fifteen minutes on 

 the surface free from the skin, the surface nuist be very 

 smooth or covered with a scum ; a high wind is siu-e de- 

 struction, and even small ripi)les make the task a hazard- 

 ous one. After the puparium is abandoned the imago 

 stands lightly on the water, holding up first one leg and 

 then another, evidently drying the feet; suddenly it takes 

 wing and disappears. This is the method in an open 

 pond or a tank ; where grass or other growth abounds 

 along the margins, it is usual for the imago to emerge in 

 such a position as to crawl directly nj) on some stalk and 

 proceed more rapidly. We have seen C. damnosus fly 

 awav in four and a half minutes from the time of emer- 

 gence, when there was no herbage to facilitate the j)i'o- 

 ceeding. From this time forth the j)rincipal object in 

 the remaining brief existence is the duty t)f reproduction. 



