A MAGGOT TRAP IX PRACTICAL USB. 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 college. 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 college 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 
larvae 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 wmether 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 corner 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 
the concrete basin was constructed a wooden platform 20 feet long 
and 10 feet wide, supported on legs 1 foot high. The framework 
of the platform 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. Each of the long pieces was supported on four legs set at 
intervals of nearly 7 feet. Across the top of the framework were 
nailed strips 10 feet long by 1J inches thick and 1 inch wide. These 
strips were nailed 1 inch apart. Plate I shows most of the details 
