If mosquitoes could be exterminated malaria and yellow 

 fever would vanish from the face of the earth. Though this 

 is manifestly beyond the power of man, still the case is not 

 hopeless for mosquitoes are not strong fliers and never travel 

 far from their breeding places. When strong winds blow 

 they seek shelter and so are seldom blown great distances. 

 A moderate wind blowing steadily in one direction may dis- 

 tribute mosquitoes several miles. Trains carry them farther 

 but since these modes of dispersal are unusual we may con- 

 clude that each locality breeds its own mosquitoes. Mosqui- 

 toes breed by thousands in still water, stagnant pools, 

 swamps, marshes, mud puddles, gutters, cesspools, sewers, 

 cisterns, rain-barrels, tin cans, in fact, wherever water 

 stands for tv/o or three weeks at a time. If these breeding 

 places can be abolished the mosquitoes will go too. In many 

 localities it is quite feasible to drain or fill in pools, swamps 

 and marshes, and not only banish the mosquitoes but also 

 improve the landscape incidentally. Cisterns and the like 

 can easily be screened and the tin cans on dumps should be 

 cared for in any case. 



A brief examination of the life history of the mosquito 

 will show that even when bodies of still water cannot be 

 abolished mosquitoes may still be controlled. The female 

 mosquito always resorts to v/ater to lay her eggs, which float 

 on the surface till the larvae, "wrigglers", hatch. These 

 larvae breathe by a tube at the posterior end of the body and 

 later metamorphose into pupae which breathe through the 

 head. From the pupa the adult mosquito emerges fully 

 formed into the air. Now fish feed voraciously on mosquitoes 

 in all these stages and the introduction of fish into ponds will 

 often exterminate the mosquitoes. Perhaps one of the most 

 useful methods of distruction, however, is in covering the 

 surface of still water with a thin film of patroleum. This 

 kills the females as they come down to lay eggs and drowns 

 the larvae and pupae by preventing their breathing tubes 

 from reaching the air. Wherever systematic efforts of this 



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