Bearded Robber Fly

(Efferia pogonias)

photo by John Borom

Robber flies are common, swift-flying predators. They have stout, spiny legs, a dense " beard " of bristles on the face, and a depression in the forehead. The  Bearded Robber Fly often overtakes deer flies or horse flies in flight, whirring at high speed. It captures them and sucks them dry while standing on a twig or leaf.