INSECTS 55 



if communities will but take the trouble to eradicate all 

 breeding places of mosquitoes. Since the mosquito, during 

 its development in the water, comes frequently to the surface 

 to secure air for breathing, a thin film of oil spread over the 

 surface of the water in which they are breeding is' a sure 

 means of killing them. But the kerosene treatment is at 

 best but a temporary means of ridding a community of mos- 



FIG. 38. Staten Island marshes before drainage. 



quitoes. The oil has to be renewed every two or three weeks, 

 especially after rains, to make sure that a continuous film 

 covers the surface. Hence, wherever possible, pools should 

 be drained, and one has but to read Dr. Doty's account of 

 his marvelous success in abating the mosquito nuisance on 

 Staten Island (see New York State Journal of Medicine, 

 May, 1908) to be convinced that this method is effective 

 (Figs. 38 and 39). Every householder should cooperate by 



