84 DRAGON FLIES VS. MOSQUITOES. 



over the box, which remained standing in the sun. 

 Twelve days afterward the first imago was noticed, and 

 the numbers increased until the sixteenth day, when quite 

 a swarm of these flies with some others filled the box. 



In crossing a plowed field about the same time I found 

 the carcass of a large rat which had been crushed by a 

 farm wagon. A strong wind was blowing at the time, 

 and the number of meat flies attracted by the odor thus 

 wafted almost concealed the body from view. A number 

 of the flies were secured and preserved, and the rat taken 

 home and after a few hours' exposure confined as the horse 

 manure had been. In the course of two weeks the per- 

 fect flies appeared. 



MOSQUITOES (Culicidfe). 



I. Natural Conditions under which Mosquitoes 



Breed. 



The life history of these insects is so well known, and 

 has been so frequently described at length, that it would 

 be a vain repetition to insert any extended account of their 

 transformations here. The eggs are laid in or near fresh 

 or brackish water, in which the larval stage is passed, and 

 a new brood appears about every three or four weeks. 

 Their period of aggressive activity is not nearly as exten- 

 sive as that of house flies, but, like them, all the stages exist 

 contemporaneously, from the frequency and interlapping 

 of the broods. 



II. Experiments in Breeding in Imitation of 



Natural Conditions. 



None were made, for the reasons stated in I. 



