Screening and Destruction 217 



Therefore traps are installed with their openings 

 turned outwards and are not used for collecting 

 the Anopheles which have already gained access 

 to the building. 



Traps are of Uttle use on unscreened houses and 

 are never used on them. 



The number of mosquitoes caught in these 

 traps has been surprisingly large and it is not 

 uncommon to catch several hundred per night in 

 one trap. 



In order to determine whether any mosquitoes 

 escape, a trap in which a number of mosquitoes 

 were confined was fastened to an empty trap. 

 None passed from one trap to the other. If they 

 could have found the openings in the trap in which 

 they were confined they would have collected in 

 the other trap. 



Mosquito traps, built after the model used on 

 the Canal Zone, are of distinct value as a prophy- 

 lactic measure in anti-malaria campaigns, as an 

 auxiliary to screening, and the destruction of mos- 

 quitoes by hand. 



These mosquito traps cost about $1.25 each 

 when made by hand by the dozen. 



