ENTOMOLOGY

MYIASIS-ITS PRE\'ENTION AND TREATMENT 203large opening at the top of the cone, screened area over the cone to admitlight from above, screened sides so as not to cast shadow around thebait, and legs about one inch high. The tent traps are not as efficientas the cone traps and this inefficiency is especially marked in somemakes of traps now being furnished the Army, which arc built with abroad bottom on either side of the tent. This repels the flies to such anextent as to make the traps almost worthless. For blow flies this darkenedarea is not so objectionable as for the house fly. While not strictlya trap, the method of covering carcasses with burlap as recently suggestedby Froggatt in Australia may be of value. Four stakes are driveninto the ground around the carcass, and the tops of these are connectedwith a heavy wire. A canopy is then put over the stakes, brought tothe ground and dirt piled on the edges. When the flies emerge they areimprisoned and soon die. If the canopy is not sufficiently large, thereis danger of many escaping through the migratory habit of the Iarvre.Kind of Bait to Use.-This point has been discussed in a previouslecture. Animal matter is best for blmv flies, and the packing-house refuseknown as "gut slime" is best of all. It is removed from intestineswhen sausage casings are made. Good baits and proper attention to killingand rebaiting are essential to best results.Poiso"",.-It is possible to destroy large numbers of flies by meansof poisoned baits. Arsenic solution (made by boiling arsenic in water)mixed with defibrinated blood, gut slime, or some other attractive baitwiII kill large numbers. This bait may be placed in covered containersto prevent dilution by rain. Cobalt may be substituted for arsenic.When carcasses can not be burned, Frogga tt has advocated slashingthem and spraying with arsenic solution. This poisons large numbersof flies and maggots and reduces the attractiveness of the carcass; somuch so, in fact, that birds and animals will not touch it.Avoidance of Attack on lIfan.-To prevent fly attack it is necessaryto have wounds promptly and properly dressed. Man should avoidexposure by sleeping in the open during hot weather, especially if thereis any trouble from catarrh or nose bleeding. Properly screened hospitalsare of much importance and individual blow flies found withinshould be promptly killed ..Avoidance of Attack to Animals.-In preventing screw-worm attackin cattle and other livestock, there are several important points to beconsidered. Breeding should be done so as to have calves come duringfall, winter or early spring months. Branding and surgical operationsshould also be done out of screw-worm season.. Care should be takento avoid mechanical injury to stock. As the screw-worm flies are worstin brushy pastures, clearing out all underbrush will be found beneficial.Since many cases develop from infestation of ticks and mange, the de-