ENTOMOLOGY

154 SANITARY ENTOMOLOGYa long series of careful studies made of many chemicals which might beapplied to manure, in ordcr to determine the effects upon the fly larvre,the bacterial activity of the manure, and the fertilizer value of the manure.The results have been p~blished in various bulletins by Hutchison, Cook,and Scales with the principal recommendation in favor of the daily treatmentof fresh manure with powdered borate at the rate of 1 pound to 16cubic feet, or 0.6~ pound per 8 bushel of manure. This will kill about90 per cent of the laiv8:!, and is harmless to the manure. Larger amounts,however, may have a deleterious effect.They also found that a water extract of hellebore, prepared by adding1h pound of powder of hellebore to 10 gallons of water, which afterstirring is left for ~4 hours, is effective at the rate of 10 gallons to every8 bushels (10 cubic feet). Likewise a mixture of % pound of calciumcyanamid and % pound of acid phosphate to each bushel of manuregives a larvicidal action of 98 per cent. Unfortunately these last tworemedies are not available at the present writing.Creosote has been recommended by British authorities, but the investigatorsmentioned above have found a deleterious effect.upon the manure.If the primary essential is destruction of fly breeding, and the otherchemicals 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 usc the most approvedmethods, but must rather obtain immediate results with materials andmeans at hand.Maggot Traps.-Hutchison discovered an application of the habitof the fly maggots of migrating from the manure piles before pupation,when he developed the maggot trap which consists of a slatted platformover a cement or metal water-filled basin (fig. 3~). Such platforms canbe built of sufficient size and number to hold the accumulations ofmanure for a period of about two weeks, after which time it is unfavorablefor house fly development. The larvre migrate from the pile and fallinto the water and drown (plate VIII).Storage in Bins.-The house fly is averse to darkness and variouscontrivances have been devised for the dark storage of manure, in pits,tightly closed boxes, windowless rooms, etc. (see plate V). For smallstable accumulations, especially in cities, perhaps this furnishes one ofthe best means of temporary storage. It is a good plan to use fly trapsin connection with manure bins (see fig. 33).Stacking.-Manure may be stacked in such a way as to greatly minimize,if not entirely prevent fly breeding. A stack built up by the drivingof the wagons over the pile and dumping thereon becomes very compactand the internal heating is quite destructive to the fly larvre. The sidesof such a pile should be compacted and the loose materials on the ground