1 genus (Basilia
) and 6 species in North America (1)
Adults are obligate blood feeders on bats; larvae remain in mother until ready to pupate (as in other Pupipara)
"These bat flies, as well as the related flat fly parasites of birds, have some of the lowest offspring numbers in the insects. Females give live birth to one (sometimes more) offspring that are nurtured in the insect equivalent of a uterus and are born alive in process that resembles true viviparity. The only times these flies leave their hosts is to deposit the larvae in a safe place to pupate. Flat flies retain their wings and ability to fly, however it seems these bat flies have lost their wings entirely. This may be allowable due to the fact their hosts return to the same sheltered roost regularly." B. Zvolanek, FB comm.
"Bat flies, on the other hand – like humans – prefer to invest a lot in a much smaller number of offspring, hoping that they will all make it to the reproductive age. Instead of laying eggs the female gives birth to a single, fully developed larva, which immediately turns into a pupa." P. Naskreki, see "Internet References" below
"In fact, because the parasites can't survive for very long on their own, the only time a female bat fly will leave its host is when the time comes to drop her larva off in a safe place – usually the wall of the bat's cave roost. Then, she'll quickly rush back, guided by the smell and warmth of her host." S. Keartes, see "Internet References" below