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 covci' thcin, 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. quinquefas- 

 ciatun, Anopheles quadrimaculatun, and others. 



quitu larva' thai liie latter can e.\ist only in high-lying or shul-iu 

 portions of the marsh over which the tide only occasionally' sweeps 

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

 value of killifish as destroyers of larva?, the problem of preventing 

 the marshes from producing countless moscjuitoes resolves it- 

 self into so draining that the water on it either will !>(> drawn 

 off at every low tide or will ])e constantly stocked with tish. A 

 munbor of workers have recently HMnarkcd on the folly of oiling 

 j)ools which could l)e stocked with tish, since tlu' oil kills tlie 

 natural enemies of the larva? and is not permanent. Instead it 

 is urged that lisli be propagated in such i)ools. The water weeds, 

 however, should Ix' icmoNcil and ox'erhanging plants cut back 

 so that the (ish can operate freely in tlicii' pursuit of larwi'. In 

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

 constructed at th(i lowest level and stocked with fish, and the 

 swamp drainccl into the pond. 



.\. fresh-water h.^h of the same fannly as the killiiish (Cyprino- 

 dontida') known as " uiillions " {(JininliiiKs pceciloidcs) has been 



