FLY, in Zoology, a large order of insects, the distinguishing characteristic of which is, that their wings are transparent. By this they are distinguished from beetles, butterflies, grasshoppers, &c. Flies are subdivided into those which have four, and those which have two wings. Of those with four wings there are several genera or kinds; as the ant, the bee, the ichneumon, &c. Of those with two wings, there are likewise several kinds, as the gad-fly, gnat, house-fly, &c. For their classification and natural history, see ENTOMOLGY.
House Fly. See MUSCA.
Pestilential Fly. See ABYSSINIA.