Mosquitoes 



of which time the skin splits on the back of the thorax and the 

 adult mosquito works itself out, resting upon the old pupa skin 

 until its wings unfold, and then flies away. The duration of a 

 single generation may be within ten days; say sixteen hours for 

 the egg, seven days for the larva and two days for the pupa. 

 This time, however, may be indefinitely extended if the weather 

 be cool. 



107 



