IMPORTANT FLIES 



109 



First necessary step in health conservation. The most sig- 

 nificant fact in the situation is that only by eliminating the 

 fly can we form any notion of how much present sickness it 

 is causing. On this account health officers everywhere are 



TOP FRAME 

 remove, to empty trap 



-'holeevery3" 



The figure may be supposed to 

 represent a model 12 inches wide, 

 12 inches tall, and 10 inches thick 

 ;i convenient size for ordinary 

 use in a city yard. The specifi- 

 cations will then be : two end 

 boards inch or inch thick, 

 12V 10 inches; four strips for the 

 top frame, Ix J inch, two 12 inches 

 and two 9 inches long ; wire for 

 top frame, 10 x 12 inches (raw 

 edges folded over inch); two 

 top shoulder strips lx inch, 11 

 inches long ; four bottom strips 

 | inch thick and 12 inches long, 

 two inch wide and two 1 inch 

 wide ; screen wire for sides and 

 bottom in one piece, 12 inches 

 wide and 41 inches long (allow 

 1 inch to fold over raw ends, 

 i inch each) 



FIG. 54. Cross section and detail of stable-window or barnyard flytrap 



These traps may be of any convenient size, to suit conditions, and may be made 

 of box boards, strips, and screen wire. It is well to plan to use wire of standard 

 widths. If used on the ground, the traps may be made without the trap-folds in 

 the sides, which do most of the catching when the trap is set in a stable window. 

 Fold the wire squarely at the angles indicated in the figure, A, fi, (', D, E, F, G, and 

 at these points snip in inch. Fold the 5-inch flaps to a right angle, turning them 

 in directions indicated by small hooks along the course of the wire (dotted line). 

 This allows the bottom ridge and the trap-folds to drop smoothly inside the end 

 boards, and the flaps are tacked to the end boards to help hold the wire in place 

 and make the trap absolutely fly tight so far as any cracks along the corners are 

 concerned. The holes in the Wire are punched by pushing ten 40-penny wire spikes 

 through the exact apex of the bottom ridge, about 1 inch apart. If good bait is 

 used, the flies may become much crowded here. (This must be a sharp 90 angle, 

 not a rounded dome, or the flies will not find the holes.) Three holes are suffi- 

 cient for the side folds. Punch all these holes after the wire is tacked in place. 

 The trap is really as simple as a box. With proper tools a boy ought to cut out the 

 end boards, rip out the strips, nail up, fold, and tack the wire, all in about one 

 hour. The main feature of the trap is the J-inch crack opening upward to the bait 



saying, in effect, " Clear the air of this universal distributor, 

 of filth, in order that we may be able to trace other ways of dis- 

 ease infection." Thus extermination of flies comes to be the 

 necessary first step toward the effective prevention of disease. 



