200 The Control of Mosquitoes 



Unless near a wall mosquitoes do not congregate 

 about the door of a screened veranda as they 

 do about a screened door in a solid waU. They are 

 too busy examining all the screened surface to 

 concentrate at its entry. 



If there is a prevailing wind direction during 

 the mosquito breeding season it is advisable to 

 have the balcony door on the windward side of 

 the house. 



Where windows have to be screened, the sashes, 

 shutters, and frames are so arranged that a per- 

 manently fixed screened frame can be fastened 

 in place. Sliding screen frames are very unsatis- 

 factory in practice; they warp and refuse to shut 

 tightly, they cost more to install and maintain, 

 and are often left open. 



A light solid door, well designed and made, 

 and rapidly self closing is preferable for a mosqiiito- 

 proof house. In damp- countries such doors 

 should be made of close-pored lumber, well dried 

 and carefully filled and varnished, or painted, 

 and designed to reduce to the minimum the 

 tendency toward sagging, warping, and swelling. 

 The doors should be provided with efficient self- 

 closing devices, and they should open outward to 

 frighten away any mosquitoes resting on or near 

 the door or hovering in the vicinity. Occa- 



