NATURAL ENEMIES OF MOSQUITOES 165 



as tliey capture other insects on the wing. The same 

 may be said of other predatory aquatic insects. Some of 

 the aquatic beetle larvae and some of the predatory water- 

 bugs undoubtedly destroy hundreds of mosquitoes. Any 

 stagnant pool, when carefully watched, will be found to 

 swarm with predatory animal life. From such a pool I 

 once took a half gallon of water which was teeming with 

 aquatic insects, including hundreds of mosquito larvae. 

 Among these insects there were three water-beetle larvoe 

 of the family Hydrophilidse, and in the course of a week 

 these three larvae practically devoured all of the other 

 animal life in the jar. 



The adult mosquito also has its natural enemies. We 

 have already mentioned the dragon-flies, and many night- 

 flying birds, such as night-hawks and whippoorwills, 

 destroy them on the wing ; and bats, of course, feed upon 

 them. An observation is on record by the late Prof. F. 

 L. Harvey, in which he states that he found six hundred 

 mosquitoes in the crop of a single night-hawk. In No- 

 vember, 1900, Mr. E. P. Salmon, of Beloit, Wis., wrote 

 me, " There is a parasite, a little red louse, which attacks 

 the mosquitoes on Madeline Island a few weeks after 

 their appearance in June, and from the time this little 

 red louse shows itself on the mosquito under the mosqui- 

 to's wings, the mosquito begins to lose his strength. 

 After a few weeks, along toward the end of July, the 

 mosquito ceases to be very troublesome and seems to be 

 fighting with his parasite for his life." This parasite is 

 probably one of the little red mites which are found 

 upon flies, and particularly upon the common house-fly. 



