134 Mosquitoes 



small ponds, and quarry holes; sun fish in ponds; 

 sticklebacks, which are bottom feeders, for ditches 

 and pools, are also useful. Top minnows and stickle- 

 backs are a good combination, making a division of 

 labour. 



Libclhila larvae, water beetles (except hydrophil- 

 lids), Corixa, and Nepa are enemies. Larvse of 

 PsoropJwra and Megarliinus mosquitoes, being can- 

 nibals, are useful in that stage. Water " scorpions," 

 isopods or " shrimps," Corethra larvae, water striders, 

 " water tigers " (the larvse of Dytiscus beetles), and, in 

 shallow ponds, dragon-fly larvse, are great aids in con- 

 trolling the mosquito pest. Dr. Smith says that 

 the larvse of dragon-flies are as little entitled to credit 

 for effective work as the adults. They are bottom 

 feeders as a rule, and usually far below the range of 

 even Culex, while Anopheles is in no danger from 

 them whatever. However, in the shallow pool on 

 the Louisiana State University campus, Dr. Dupree 

 and I have watched the larvse do some very effective 

 work on Cnlex, and have seen the adults snatch 

 mosquitoes as they were issuing from the pupa skins. 



The adult mosquitoes also have enemies in the 

 shape of a mite or tick, about .5 mm. long, which 

 fastens upon them, sucking the fluids from the body ; 

 also a tiny fly, about .2 mm. long. After the mos- 

 quito has had a full meal, and the abdomen is dis- 

 tended, both fly and tick will sometimes manage to 

 penetrate to the stomach with their beaks and suck a 

 meal of blood — decidedly a case of thief rob thief. 



At times the mosquitoes are attacked by a parasitic 

 round-worm, Agamomermis culicis. It is found in 



