YII 



Nil fund /'Jitcni'ics of Alosr/fflfoes 



WHEliE mos(|uitoes exist in rain-water l)uc'kets 

 and l)arrels they are apt to have none or very few 

 natural enemies. Their principal enemies when 

 in the aquatic larval and pupal stages are fishes and carniv- 

 orous insects. Most carnivorous insects are rather slow 

 breeders, and as a consequence they seldom deposit their 

 eg-g-s except in rather permanent pools, and naturally 

 fish are found only in such places. There are, however, 

 other enemies aside from these. Dr. C. W. Stiles informs 

 me that during the summer of 1889, when working with 

 C. H. Hurst, they collected at Leipsic a large number of 

 mosquito larvno and pupno, and that many of them died in 

 the laboratory. Upon opening one of the bodies, which 

 was quite distended, he found a species of Mermis, one of 

 tlie hair Avorms or hair snakes, coiled up in the body cav- 

 ity. Examination of other dead larvjTO or ytnpiv disclosed 

 the fact that nearly every one was ])arasitized by the same 

 sj)ecies of Mermis. He showed the worms to Professor 

 lAudolph Leuckart, who inrormed him that he had re- 

 peatedly found the same Nematode in former years, and 

 that he had observed that in years wIkmi mosquitoes were 

 numerous the worm is very scarce. This h'd him to be- 



156 



