18 FARMERS BULLETIN 679. 
place for pupation. This migration takes place mostly at night, and 
the larvee sometimes crawl considerable distances away from the ma- 
nure pile. Now it is possible by means of a very simple arrangement 
called a maggot trap to destroy fully 99 per cent of all maggots 
breeding in a given lot of manure. A successful maggot trap which 
the Maryland Agricultural College constructed at the college barn 
Jast year is shown in figure 14. The trap was designed by the junior 
author and constructed under his supervision. The manure, instead 
of being thrown on the ground, is heaped carefully on a slatted plat- 
form, which stands about 1 foot high. This particular platform meas- 
Fic. 14.—A maggot trap for house-fly control. View of the maggot trap, showing the 
concrete basin containing water in which larve are drowned, and the wooden plat- 
form on which manure is heaped. (From Hutchison.) 
ures 10 by 20 feet. There are six 2 by 4 pieces running lengthwise 
2 feet apart. Across these are nailed 1-inch strips with $ to 1 
inch spaces between them. The wooden platform stands on a con- 
crete floor, and a rim or wall of concrete + inches high surrounds the 
floor. The floor slopes a little toward one corner, from which a pipe 
leads to a small cistern near by. This pipe is plugged with a stopper 
of soft wood, and the concrete floor is filled with water to a depth 
of 1 inch in the shallowest part. The manure is then heaped on the 
platform each morning when it is removed from the stable. Flies 
will lay their eggs on the manure as usual, but the maggots, when 
they have finished feeding and begin to migrate, crawl out of the 
