460 



MOSQUITOES 



great tidal salt marshes of the New Jersey coast were the various 

 species of killifish. These fish abound wherever the marshes 

 are constantly flooded and push into places where there is barely 

 enough water to cover them, and are so active in destroying mos- 



FiG. 207. One of the first places to clean up in a mosquito campaign. A 

 favorite breeding place for such annoying or dangerous species as the yellow fever 

 mosquito, Aedes calopus, the house mosquitoes, Culex pipiens and C. guinquefas- 

 ciatus, Anopheles quadrimaculatus, and others. 



quito larvse that the latter can exist only in high-lying or shut-in 

 portions of the marsh over which the tide only occasionally sweeps 

 and to which the " killies " do not penetrate. Knowing the 

 value of killifish as destroyers of larvae, the problem of preventing 

 the marshes from producing countless mosquitoes resolves it- 

 self into so draining that the water on it either will be drawn 

 off at every low tide or will be constantly stocked with fish. A 

 number of workers have recently remarked on the folly of oiling 

 pools which could be stocked with fish, since the oil kills the 

 natural enemies of the larvae and is not permanent. Instead it 

 is urged that fish be propagated in such pools. The water weeds, 

 however, should be removed and overhanging plants cut back 

 so that the fish can operate freely in their pursuit of larvse. In 

 the case of swamps it is suggested that a permanent pond be 

 constructed at the lowest level and stocked with fish, and the 

 swamp drained into the pond. 



A fresh-water fish of the same family as the killifish (Cyprino- 

 dontidffi) known as " millions " (Girardinm pmciloides) has been 



