A MAGGOT TEAP IN PEACTICAL USE, 9 



and stables in the immediate vicinity, some of these marked flies 

 fomid their way to the college barn. Here two of this lot were 

 recovered within the first 24 hours, and a third one during the third 

 24-hour period. That no flies were recovered at the kitchen is to be 

 explained by the fact that the kitchen was closed and there was 

 nothing there to attract flies. 



A second lot of about 500 flies, sprayed with rosolic acid, were liber- 

 ated at the dairy barn (A) of the experiment station, 700 yards due 

 east from the college stable. The distance from the kitchen is slightly 

 less. They were liberated at 3.30 p. m. September 1. On September 

 3 two marked flies were fomid on papers exposed at the dairy barn, 

 but none was recovered at the college stable or kitchen. A strong 

 southwest wind was blowing at this time and may have had some 

 influence on the result. It is hardly to be doubted that when the 

 kitchen is in use numbers of flies from this source are attracted to it. 

 The manure pile back of the dairy barn was found to be heavily 

 infested at all times during the summer, and flies bred out here by the 

 thousands. 



In a third experiment about 800 flies marked with powdered red 

 crayon were liberated on September 15 at the stable marked by 

 the letter C (fig. 1). Within the first 24 hours 11 marked flies were 

 recovered on fly papers at the garbage pails, and two more during 

 the second 24-hour period after liberation. No marked flies were 

 recovered at the college stable in this experiment. The kitchen was 

 in use at this time, and it must be considered significant that the 

 flies were recovered only at the kitchen, although they had to pass 

 right by the stable. This indicates the sharp rise in fly counts at 

 the kitchen when it reopened in September. 



The same thing happened on September 22. A lot of about 600 

 flies sprayed with rosolic acid had been liberated on September 21 

 near the stable marked on the map by the letter D (fig. 1). None of 

 these were recovered at the coUege stable, but three were found within 

 the first 24 hours on papers exposed on the garbage pails at the 

 kitchen. 



These few experiments indicate that a large number of the flies 

 which congregate at the college kitchen and stable come from near-by 

 breeding grounds other than the manure pile at the college barn. 

 And it may be said that a reduction of from 67 to 76 per cent in the 

 average number of flics, in spite of the proximity of these other 

 breeding places, speaks well for the efficiency of the maggot trap. 



SOME DEFECTS OF THE MAGGOT TRAP. 



The experience during tl)e past season witii tiie platform maggot 

 trap has dir(!ct cd attention to certain defects in its practical working. 

 Tliese defects, however, are not of such a soi'ious nature that they 



