6 



Farmers' Bulletin 73^ 



By foldin<r in and crimping the ed<ies of the wire over the wire 

 hoop it will remain in position without difficulty and the edj^es of the 

 screen disk are used to lift the top of the trap out for emptying; flies. 

 It is important to have flie screen top fit the inside of the cylinder 

 A'ery snujrly at all points. If there is any space left where flies can 

 escape it is a jjood plan to bind the ed<re of tlie top with a strip of 

 burlap. This not only helps to close the openings but keeps the hoop 

 in place and aids in removing the top. Another difference is that the 

 screen forming the sides of the cylinder is placed on the inside of the 

 hoops and legs, the frame being built first and then the cylinder 

 formed by tacking the wire on the inside of the hoops and nailing in 

 along the upright strips and against the wire short pieces of laths 



with their upper ends 

 against the lower edge 

 of the hoop forming 

 the top of the trap 

 and extending down- 

 ward along the legs 

 about two-thirds of 

 their length. These 

 strips hold the wire in 

 place and give rigidity 

 to the trap, and they 

 are thick enough to 

 project beyond the in- 

 ner surface of the hoop 

 and form a support 

 upon which the edges 

 of the screen top rest. 

 Conical traps with 

 steel frames are satis- 

 factory, but they are 

 less easily rescreened. 



2^- 'jr^ These, of course, can 



be constructed only by 

 shops with consider- 

 able equipment. Traps 

 constructed with a 

 wooden disk about the base of the cone, and a similar disk around 

 the top to serve as a frame, or those with a square wooden frame at 

 the bottom and top, with strips up the corners, are fairly satisfac- 

 tory. It should be borne in mind that the factor which determines 

 the number of flies caught is the diameter of the base of the cone, if 

 other things are equal. Therefore, the space taken up by the wooden 

 framework is largely wasted, and if it is too wide it will have a de- 

 terrent effect on the flies which come toward the bait. P^or this 

 reason it is advisable that the wood around the base of the cone 

 .•should be as narrow as consistent with strength — usually about 3 

 inches. 



Under no condition should the sides or top of the trap he of solid 

 material, as the elimination of light from the top or sides has been 

 found to decrease the catch from 50 to To per cent. 



Fio. 4. — Tent flytrap. When the tnip is set up the screen 

 box, A, fits in the base, B, and two pans of bait are 

 placed beneath the tent. C, Hole in screen at apex of 

 tent 



