PREVENTIVE MEASURES 215 



wire gauze trap was set over a hole on the sunny side 

 of the top of the can. The flies crawled in, attracted 

 by the odor of food, and attempted to escape by the 

 only opening through which the light came, thus enter- 

 ing the trap. 



Another form devised by Hodge had a tight can 

 cover, the trap being contained within the cover. The 

 trap itself forms the only entrance to the can, and the 

 flies attracted by the odor enter the trap. Another 

 trap devised was a wire gauze cylinder fitting over a 

 tomato can, the can being filled with attractive sub- 

 stances, and the trap being arranged so as to be scat- 

 tered around stables or barnyards or wherever flies 

 happen to be congregating or breeding. 



He made still another arrangement for a screen for 

 a stable cellar or manure pit window, making a small 

 hole in the screen near the top and providing the screen 

 with narrow strips of tin or wood to guide the flies to 

 the hole; the hole, of course, leads into a wire gauze 

 trap, where all the flies that emerge will be caught. In 

 the same way he made another, also provided with 

 guiding strips, on the outside, and furnished with a 

 trap on the inside, so as to catch all of the flies that 

 might be attracted to the stable to lay their eggs. This 

 latter idea he has not yet tested, but he argues that 

 if the outside flies were shut out by screens they would 

 certainly find some other breeding place in which to 

 lay their eggs'. 



On the habit that flies have of being attracted to 

 kitchens by the odor of the cooking or by the warmth 



