Hippoboscidae, the
louse flies or
keds, are obligate parasites of mammals and birds. In this family, the winged species can fly at least reasonably well, though others with vestigial or no wings are flightless and highly apomorphic. As usual in their superfamily Hippoboscoidea, most of the larval development takes place within the mother's body, and pupation occurs almost immediately.
(Wikipedia)