As the latter do not seem to be a monophyletic group, it is conceivable that bat flies cannot be united into a single family.

[1] They are flattened, spiderlike flies without eyes or wings, and as such bear very little resemblance to other Dipterans.

These flies are seldom encountered by general collectors, as they almost never leave the bodies of their hosts.

The family is primarily found in the Old World tropics; a few of the 274[2] known species occur in the Neotropics and in Europe.

One of the key morphological features of Nycteribiidae is their highly reduced compound eyes.