FLESH-FLY, BLOW-FLY, or MEAT-FLY. Any of several large, noisy, blue or green flies of the house-fly type, which lay their eggs on exposed wounds, meat, or carrion. A very con spicuous one is a large 'blue-bottle' fly (Celli phora erythrocephala), rather dull in color, with a rust-red forehead and black spines on the thorax. It is the common 'blow-fly' of Europe, whose maggots are called 'gentles' and used as bait by English anglers. Another familiar Brit ish species (Barcophage curnaria) is rarely seen in America, where its place is taken by a similar scavenger-species (Sarrophage sarraccnie) . A third well-known American species is the green bottle (Lncilia caner), which often enters houses. This and the preceding species frequently lay their eggs in the putrid mass of insects caught by the plants of the fly-trap (Sarracenia). In the Western States a most troublesome kind is the screw-worm fly (Compsomyia macellaria), which ranges throughout the warmer regions of both Americas, and sometimes attacks wounds or diseased parts (as the nostrils) of men as well as domestic animals. Indeed, the evil effects of several sorts of flesh-flies (including the small gray ones of the genus lIelicobia) are referred to in medicine by the term miasis. The stable fly (Stemoxys calcitrans) should also be men tioned here.
The breeding habits and life history of all these flies are essentially similar. The eggs are laid in packets on dead animals or upon raw or even cooked meat, each packet containing from 3 to 100 eggs. The instincts which guide the fly
to just the food its larva will require are as pre cise as they are curious. Prof. Jacques Loeb re cords in his Physiology of the Brain (New York, 1900) that where pieces of lean meat and of fat from the same animal were exposed together "the Ily never failed to lay its eggs on the meat and not on the fat ;" furthermore, lie was unable to rear the larva on the fat. Ile believes the at. traction and choice are due to chemitropism in the parent fly. The larva? issues in from twenty to twenty-four hours, and buries itself in the car rion, feeding continuously for two weeks, when it crawls aside into some protected place and trans forms to pupa, in which stage it remains from two days to several weeks. There are soTeral genera tions each year, and the part which these insects play in the rapid removal of decaying carrion is very important. Unfortunately these insects also attack the fresh wounds of living animals, with most injurious effects; and Paekard states, in regard to Celli/thorn -eon itoria, that it grievously tormented wounded soldiers on the battlefield during the Civil War. Careful cleaning of in fected wounds of aniinals with dilute carbolic acid, and covering them with a dressing of tar, are remedial measures. Consult: Osborn. "In sects Affecting Domestic Animals," in United Steles Bcpart meat of Agriculture, Bivision of Entomology. Bulletin 5 (Washington, 1896).
See FLY; TSETSE- FLY.