84 NATURE-STUDY REVIEW [12:2— Feb., 1916 



this labor and nuisance, we leave from one to twelve per cent to 

 keep up the egg laying. 



The latest scheme of the Department experts is the cement-basin 

 maggot trap described in Farmers' Bulletin, 679, July 14, 1915. 

 For the accommodation of the manure from four horses — while 

 it pollutes the air and goes to waste for four months — a slatted 

 platform is built 20 feet long and 10 feet wide. The legs of this 

 platform support it one foot above the cement basin, four inches 

 deep — size not specified — which looks from the picture to be at 

 least 11 by 22 feet. This basin drains to one corner and is kept 

 with water one inch deep in the shallowest place, and it must be 

 drained and the accumulated filth, with the living, dead and rotten 

 maggots that may be caught in it scrubbed or hosed out of it at 

 least once a week — a job disagreeable enough to drive any hired 

 man away from the place where he was required to do it. This 

 device depends for its effectiveness on the fact that maggots, 

 when they reach their growth, tend to migrate out of the pile 

 to a dryer place in which to pupate. Hence, again, the manure 

 must be kept "well moist" i. e., " a few minutes each day are neces- 

 sary to water the manure after the stable cleanings have been 

 added to the heap." Properly managed this trap is said to catch 

 99 per cent of the maggots and to reduce the flies "at the barn 

 and around the college kitchen from 67 to 76 per cent" (when 

 $0.10 worth of screen wire in a trap managed with one per cent 

 of the time and labor, and one one-thousandth part of the 

 nuisance, might have cleaned up 100 per cent of the breeders). 



No statement of cost, nor anything complete as to specifications, 

 is given for this demonstration maggot trap at the Maryland 

 Agricultural College. It is said, however, to be 'simple, easily 

 constructed, and cheap." "Practically the only cost is the 

 initial one of construction." Certainly no wooden, slatted plat- 

 form could stand up under a mass of " well moist" manure for many 

 months, and if the basin is to hold water and withstand heaving and 

 cracking in winter, it would need to be solidly built on well drained 

 foundations at a cost for labor and materials of probably not 

 much below $50.00 for the size indicated. In the end we have 

 such a filthy looking outfit, and one so likely under the least 

 neglect to breed mosquitoes or raise a stench, that no town or city 

 health officer could possibly grant a permit to build one within 

 his jurisdiction, and since no farmer would ever be impractical 



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