IOO 



to shun mosquito larvae, allowing them to reach maturity. Care 

 should be taken to see that growths in the pools are removed, 

 allowing the fish access to every part of the water surface. I 

 have observed mosquitoes propagating in pools containing enough 

 fish to keep them free, but separated from; the larvae by growths 

 through which the fish could not penetrate. 



A record kept of the adults, taken in the night collections will 

 serve to show what kinds of mosquitoes are on the wing in 

 greatest numbers. Those in charge of campaigns, in their eager- 

 ness to control the varieties of mosquitoes which are most trouble- 

 some, may neglect other varieties and find, too late to remedy 

 the condition, that .weather conditions have favored these mosqui- 

 toes. It is important, therefore, to study the habits of each 

 variety of mosquitoes breeding in the territory, and keep a record 

 of prevailing weather conditions in order to determine how the 

 frequent changes of the weather must be met. As, for instance, 

 in a drought the pools dry up but the brooks dry out in spots 

 and the breeding is transferred from pools to> brooks. In a wet 

 spell the conditions are reversed. 



The records of permanent breeding places should not be 

 buried in filing cabinets, but placed where they remain before 

 the eyes of those in charge of them, and checked up weekly. It 

 should be an established rule that once mosquitoes are found 

 breeding, the conditions of which cannot be readily abolished, 

 they should never be allowed to reach the winged stage of de- 

 velopment in such places again, as these places should be fre- 

 quently inspected, and oiled when necessary, 



I have tried in this paper to give you a general outline of how 

 a campaign of fresh-water mosquito control should be carried 

 on, but it is, in reality, how we are doing the work in Essex 

 County. You may be interested to learn what our results have 

 been. 



We have been working four years ; that we have reduced the 

 mosquitoes in numbers nobody will deny; that we still have 

 enough mosquitoes to make their presence felt at times we all 

 admit, but this, no doubt, is due to the enormous sewage-polluted 

 salt meadows where fresh-water mosquitoes breed. 



