about 20, see text Prolepsis is an insect genus of mainly neotropical Diptera in the family Asilidae or robber flies.

Ventral side of the femur of the middle leg pair often with a thick patch of short and stout spines.

Prey are probably taken from a wide variety of insect orders: Robert Lavigne's Predator-Prey Database for the family Asilidae[2] has one record for Prolepsis lucifer feeding on the dung beetle Canthidium globulum and four records for Prolepsis tristis feeding on the following identified prey species: the clown beetle Epierus formidolosus, the blister beetle Epicauta trichrus, the hoverfly Eristalis dimidiatus and the Western honeybee Apis mellifera.

Herschel Raney's webpage for Prolepsis tristis includes example images of cannibalism and color variation among males.

[3] Larval stages have received little study to date, but the first instar larvae of P. lucifer are reported to prey voraciously on the subterranean scale insect or ground pearl Eurhizococcus brasiliensis, with possible biocontrol applications for protection of grapevines in Brazil[4][5] These 20 species belong to the genus Prolepsis:[6][7] Combined analysis of morphological and molecular characters places Prolepsis tristis in a clade corresponding to the subfamily Stenopogoninae, without however providing direct support for monophyly of this subfamily.