92 NATURE-STUDY REVIEW [12:2— Feb., 1916 



together as shown in 2 and 3 in Fig. 6. It is easier to tack the wire to one end 

 board, to which its top-shoulder and bottom strips have been nailed, and then 

 set the other end board in place. The complete specifications for a trap 12 by 

 12 by 10 inches will be: 



Two one-half inch end boards 10 by 12 inches (with cleats if necessary). 

 Two top shoulder strips one inch by one inch by 1 1 inches long. Two bottom 

 strips one-quarter inch by one-half inch by twelve inches long. Two bottom 

 strips one-quarter by one inch by twelve inches long. Two top frame strips one- 

 half inch by one inch by twelve inches long. Two top frame strips one-half 

 inch by one inch by nine inches long. Screen wire for top frame ten inches by 

 twelve inches. Screen wire for sides and bottom twelve inches by 39^2 inches. 

 (Fold down wire one-quarter inch at each end, and fold squarely at angles 

 indicated in Figs. 5 and 6. Cut the wire one-half inch in at angles A, B, C, D, 

 E, F, G, in Fig. 5 and bend the one-half inch flaps at right angles so that bot- 

 tom lidge and trap folds of sides can drop smoothly between end boards. 

 Begin tacking the wire at bottom corners then draw to top corner and tack 

 so that the trap folds at B and F are not less than 60 degrees. Flies will not 

 crawl up to the holes, if the folds are too sharp. Finally punch one-quarter 

 inch holes three inches apart in the side folds and one inch apart in the bottom 

 ridge, This is done by setting in as many spikes as there are holes, then draw- 

 ing them out together — to avoid closing some holes while the others are being 

 punched. 



The first model of this trap merely set on a pile of filth where flies were 

 swarming caught 37 y% quarts in one week (about 370,000) without bait or 

 attention of any kind. This ought to prove a Getthelastone proposition 

 for dairies and farm barnyards, and if for a few cents worth of screen wire 

 we can let the breeders trap themselves at this rate, why resort to the more 

 expensive and laborious methods? The boys, in connection with their manual 

 training, can make models for demonstration, and can see to it that the barn- 

 yards are fitted up with them early, and if this is done for every home there 

 may be no need for screen windows or doors so far as flies are concerned. 



The latest addition to this trap is a bottle of formalin (four teaspoons full 

 to the pint of water) stoppered with wicking and hung to one end board 

 inside the trap. Flies are thirsty animals and drink the formalin water as 

 fast as caught. This device does away with the objection some people feel 

 to seeing the flies buzzing around — "suffering" — in the trap, keeps the trap 

 cleaner, and makes it possible to empty it any morning without having to 

 spray with gasolene or formalin to kill the flies. Other poisons might be used, ' 

 if at hand. 



Fly Foods and Baits — Management of Traps. Study and 



observe continually all the things flies are most strongly attrac- ; 



ted to about the home. We need to study the foods and feeding 



of flies even more carefully than we do the materials in which 



they breed. They cannot lay eggs until they find food to make 



them out of. In every case in which the traps are not catching 



all the flies the reason is that they are finding food outside the 



traps. We must. hunt this up and bury or burn it, and when we do 



this thoroughly, one trap is just as good as ten about a barnyard: 



for it may take a fly but a few seconds to go a quarter of a mile 



toward the only food it can smell. The idea is to keep the most 



attractive bait we happen to have under the trap all the time. 



Fresh fish or poultry cleanings (will attract all of the blow flies 



about the place, as well as the house flies) milk, both fresh and 



