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Robber Fly sucking the life out of a Common Whitetail Dragonfly.
The Asilidae are the robber fly family. They are powerfully built, bristly flies with short, sharp, stout sucking mouthparts. The name “robber flies” reflects their notoriously aggressive predatory habits; they feed mainly on other insects and they largely wait in ambush and catch their prey in flight.
The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis.
Robber flies are not to be trifled with. Capable of immobilizing bees, wasps and other insects larger than itself, robberflies catch their prey in mid air. As with other aerial predators, robberflies have excellent vision, characterized by two conspicuous compound eyes. The mouthparts of this family have been modified to a stabbing proboscis. Flies were revered by the ancient Egyptians who awarded a military honor in the form of a golden fly pendant.