Robber flies often perch on the leaves or stems of low plants waiting until suitable prey flies by, and then attack it in the air. They have long, strong, spiny legs for grabbing prey, and piercing-sucking mouthparts for consuming it. Robber flies prey on a variety of insects, including bees, beetles, bugs, dragonflies, grasshoppers, flies, leafhoppers and wasps. Once they capture an insect, they pierce it with their short, strong proboscis, or mouthpart, and inject their saliva into it. The saliva of robber flies contains enzymes that paralyze the insect and digest its insides, which the robber fly then drinks. The pictured robber fly is feasting on the innards of a stink bug it just captured.