A MAGGOT TRAP IN PRACTICAL USE. 
13 
the diagram, to have a cistern located between the platforms and a 
pump that could be used in applying water to both piles. In making 
plans for a maggot trap one must tako into consideration the volume 
of manure produced and the length of time it must remain on the 
platform. As previously stated, it will he safe to estimate that the 
production of manure per horse per day is 2 cubic feet and that after 
10 days it will he practically free from maggots, provided it lias been 
well watered. 
THE INFLUENCE OF THE MAGGOT TRAP ON THE VALUE OF THE 
MANURE. 
Plate III illustrates an all-too-common method of keeping manure. 
It covers a large area of ground, and no attempt at heaping has been 
made. The manure in such a pile is loose and shallow, and air 
penetrates into practically all parts. These are the conditions 
Fig. 4. — Imaginary cross-section of aa arrangement suggested for use where manure production is large. 
a, Pump; c, concrete floor and walls of cistern; o, outlet pipes leading from floor of maggot trap to 
cistern; p, platform maggot trap; t, cistern for liquid manure; g, ground level. (Original.) 
which give rise to the maximum loss of ammonia and nitrogen. It 
also happens that the conditions which tend to the loss of nitrogen 
are the same which favor the development of fly larvae. An immense 
surface is exposed for deposition of eggs, and the penetration of air 
makes it possible for larvae to feed in practically all parts. The 
fresher portion of the manure shown in this photograph was found 
heavily infested all through the season. 
It has been shown that the losses occurring in manure thus care- 
lessly stored will vary from 30 to 64 per cent of the total amount of 
nitrogen (Beal, 1906), and that by careful methods of storage this loss 
may be reduced to 15 per cent. Several methods of storage for the 
purpose of preventing loss of ammonia and nitrogen have been 
proposed. Among others is that recommended by Deherain, Beal, 
Thome, Ringelmann, and others, which consists hi keeping the manure 
compactly heaped and well watered. Both heaping and watering 
tend to prevent the penetration of air and thus check the destructive 
