198 NA TURE-STUD Y RE VIEW [6:7-Oct., 1910 



diameter and a half inch deep, which will hold a respectable 

 amount of selected table scraps and will not need to be filled more 

 than once a day. Flies seek their food entirely by smell, and in 

 order to attract them, we must use enough bait to give off a 

 goodly volume of odor, or they will go to the kitchen windows 

 where the enticing odors are stronger. 



Many other outdoor traps can be devised on the same prin- 

 ciple, viz., that a fly will crawl in to food anyway it can and then 

 in leaving will crawl or fly up toward the light. With a little 

 screen wire and some thin wooden slats a kitchen window screen 

 may be converted into a fly trap which will catch every fly that 

 seeks entrance, and the whole contents of the kitchen then be- 

 comes the bait. Another device, which the writer has tried, is to 

 transform the garbage can into a huge fly trap. The cover is gen- 

 erally loose enough to be pushed over to the sunny side where it 

 may be lifted a crack with a bit of chip so that the flies can crawl 

 up and into the can. Now, by cutting a hole in the center of the 

 top and setting a trap like that shown in the figure over the hole, 

 every fly that visits the garbage is caught. 



Carrying the war still further into Africa, for very little the 

 window or windows of a stable cellar or manure pit may be 

 screened with a crack at the top of the window so arranged that 

 every fly that either attempts to enter or leave the place crawls 

 into a trap. By converting the window screens of a stable where 

 horses and cows are kept into fly traps, we might, along with the 

 filth fly, do away with that fiendishly bloodthirsty pest of all ani- 

 mals, the stable fly. These insects inflict upon the brute life of 

 the country more torment by a hundred fold than all the animal 

 suffering caused by man. 



I have been working along the above lines only casually as 

 I have had a few minutes now and then, but I have done enough 

 to be convinced that any country home — a half mile away from 

 its nearest ignorant neighbor — or any town or city could com- 

 pletely exterminate the filth fly by intelligent and co-operative 

 effort during the months of April and May of any year. 



For the isolated home the only condition necessary is intelli- 

 gence enough to keep the traps baited and set until the very last 

 pair of flics which emerge from the manure about the place have 

 been caught. Then there will be no more to go back to the barn- 

 \ ards to breed the millions that form the summer broods. A gen- 

 eration of flies may go from egg to egg in ten days ; and it has 

 been estimated that if all the progeny of a pair were to find food 



