humpbacked fly, (family Phoridae), any of numerous species of tiny, dark-coloured flies with humped backs that are in the fly order, Diptera, and can be found around decaying vegetation. Larvae may be scavengers, parasites, or commensals in ant and termite nests. Some species have reduced or no wings.
The name coffin fly is based on the fact that in some species, the larvae feed on corpses, including humans.