Botfly

Botflies, also known as warble flies, heel flies, and gadflies, are a family of flies technically known as the Oestridae. Their larvae are internal parasites of mammals, some species growing in the host's flesh and others within the gut. Dermatobia hominis is the only species of botfly known to parasitize humans routinely, though other species of flies cause myiasis in humans. A botfly, also written bot fly, bott fly or bot-fly in various combinations, is any fly in the family Oestridae. Their lifecycles vary greatly according to species, but the larvae of all species are internal parasites of mammals. Largely according to species, they also are known variously as warble flies, heel flies, and gadflies. The larvae of some species grow in the flesh of their hosts, while others grow within the hosts' alimentary tracts. The word 'bot' in this sense means a maggot. A warble is a skin lump or callus such as might be caused by an ill-fitting harness, or by the presence of a warble fly maggot under the skin. The human botfly, Dermatobia hominis, is the only species of botfly whose larvae ordinarily parasitise humans, though flies in some other families episodically cause human myiasis and are sometimes more harmful.