Fly

Fly, a popular name best restricted in its simplicity to the insects forming the order Diptera, but often so widely used with a prefix—e.g. butterfly, dragon-fly, may-fly—as to be virtually equivalent to insect. The flies properly so called have two delicate, unfolded wings with predominant longitudinal veins, hind wings modified into balancers (halteres) or rarely absent, and mouth parts in general adapted for sucking. The larva is usually a legless maggot, or has secondary 'false' legs. Guats, mosquitoes, midges, daddy-long-legs, gall-flies, blow-flies, bluebottle-flies, bot-flies, forest-flies, and house-flies are noticed separately. The 'Spanish fly' or Cantharis (q.v.) is a beetle.