Wikipedia
Streblidae
The Streblidae are flies in the superfamily Hippoboscoidea, and together with their relatives the Nycteribiidae, are known as bat flies. They are winged or wingless ectoparasites of bats, and often have long legs. They appear to be host-specific, with different species of bat flies occurring only on particular species of bat hosts, sometimes with multiple species of flies sharing a host bat.