154 SANITARY ENTOMOLOGY 



a long series of careful studies made of many chemicals which might be 

 applied to manure, in order to determine the effects upon the fly larvae, 

 the bacterial activity of the manure, and the fertilizer value of the manure. 

 The results have been published in various bulletins bj' Hutchison, Cook, 

 and Scales with the principal recommendation in favor of the daily treat- 

 ment of fresh manure with powdered borax at the rate of 1 pound to 16 

 cubic feet, or 0.62 pound per 8 bushel of manure. This will kill about 

 90 per cent of the larviE, and is harmless to the manure. Larger amounts, 

 however, may have a deleterious eff^ect. 



They also found that a water extract of hellebore, prepared by adding 

 % pound of powder of hellebore to 10 gallons of water, which after 

 stirring is left for 24 hours, is effective at the rate of 10 gallons to every 

 8 bushels (10 cubic feet). Likewise a mixture of l/o pound of calcium 

 cyanamid and 1/2 pound of acid phosphate to each bushel of manure 

 gives a larvicidal action of 98 per cent. Unfortunately these last two 

 remedies are not available at the present writing. 



Creosote has been recommended by British authorities, but the investi- 

 gators mentioned above have found a deleterious effect upon the manure. 

 If the primary essential is destruction of fly breeding, and the other 

 chemicals are not available for treatment, creosote treatment is effective, 

 and there will still unquestionably be fertilizing value to the manure. 

 Army sanitarians, especially, can not always use the most approved 

 methods, but must rather obtain immediate results with materials and 

 means at hand. 



Maggot Traps. — Hutchison discovered an application of the habit 

 of the fly maggots of migrating from the manure piles before pupation, 

 when he developed the maggot trap which consists of a slatted platform 

 over a cement or metal water-filled basin (fig. 32). Such platforms can 

 be built of sufficient size and number to hold the accumulations of 

 manure for a period of about two weeks, after which time it is unfavorable 

 for house fly development. The larvae migrate from the pile and fall 

 into the water and drown (plate VIII). 



Storage in Bins. — The house fly is averse to darkness and various 

 contrivances have been devised for the dark storage of manure, in pits, 

 tightly closed boxes, windowless rooms, etc. (see plate V). For small 

 stable accumulations, especially in cities, perhaps this furnishes one of 

 the best means of temporary storage. It is a good plan to use fly traps 

 in connection with manure bins (see fig. 33). 



Stacking. — Manure may be stacked in such a way as to greatly mini- 

 mize, if not entirely prevent fly breeding. A stack built up by the driving 

 of the wagons over the pile and dumping thereon becomes very compact 

 and the internal heating is quite destructive to the fly larvae. The sides 

 of such a pile should be compacted and the loose materials on the ground 



