Robber flies are part of the Asilidae family which contains over 7000 species world wide. Robber flies all have two large compound eyes, bristles protruding from their face, and a stout beak like mouth. They use this beak, proboscis, to inject their prey with neurotoxin and proteolytic enzymes which paralyze the prey and break down its insides so that the robber fly can drink the protein though it's proboscis. Typical prey includes flies, grasshoppers, beetles, moths, dragonflies, damselflies, butterflies, bees and other insects.