A MAGGOT TRAP IN PRACTICAL USE. 3 



With the exception of the college stable, there were no breeding 

 places for flies within 400 yards of the kitchen. The stable, indicated 

 by the letter C on the map, is approximately 400 yards from the 

 kitchen and about 200 yards from the college stable. Other stables 

 are located some 400 to 500 yards west of the college stable, the dis- 

 tance from the kitchen being about 100 yards greater. 



Another extensive breeding place was found in the large collec- 

 tions of manure at the barns of the experiment station, located 

 about 700 yards northeast of the coUege. This is indicated on the 

 map by the letter A. 



PLAN OF EXPERIMENT. 



With these conditions prevailing, it was planned to construct a 

 maggot trap large enough to take care of the entire manure produc- 

 tion at the college barn, with the idea that if the trap proved effective 

 there should appear a marked decrease in the prevalence of flies, not 

 only at the barn but at the coUege kitchen. To determine whether 

 or not the trap was effective the following three lines of observation 

 were undertaken: (1) By collection and careful estimate of the 

 larvie caught by the trap and subsequent search for puparia in the 

 manure, to get some idea of the percentage destroyed; (2) by making 

 numerous fly counts during the season to find out whether the 

 prevalence of flies at the kitchen and stable was decreased; and (3) 

 to determine whether any of the flies at the college came from near- 

 by breeding grounds (A, B, C, etc.) other than the manure heap at 

 the college stable. 



THE MAGGOT TRAP. » 



The maggot trap used in this experiment was designed and con- 

 structed as follows. First, a concrete floor was prepared 22 feet long 

 and 12 feet wide. Around this floor was a rim or wall of concrete 4 

 inches high and 4 inches thick. An outlet pipe 4 inches in diameter 

 was fitted in one comer toward which the floor sloped a little so that 

 water would run out easily. Water was retained in the concrete 

 floor by stopping the pipe outlet with a plug of soft wood. The pipe 

 outlet led to a small cistern 5 feet square and 4 feet deep, the walls 

 and floor of which were made of concrete. Standing on the floor of 

 tlie concrete ba.sin was constructed a wooden platform 20 feet long 

 and 10 feet wide, supported on legs 1 foot high. The framework 

 of the platff)rm was made of 2 by 4-inch studding. There were 6 of 

 these pieces running lengthwise 2 feet apart, and one fastened across 

 each end. Eaeli of \\ui long pieces was supported on four legs set at 

 intervals of nearly 7 f(!et. Across tlie top of the framework were 

 nailed strips 10 feet long by \\ indies thick and 1 inch wide. TJieso 

 strips were luiiied I inch apmt. Plate 1 shows most of tlu^ details 



