Eocene Green River Robber Fly
Robber Fly aff. Stenocinclis sp.(Scudder)
Green River Formation
Parachute Creek Member
Middle Eocene
Uintah County, Utah
This specimen shows the thorax, abdomen and head of a robber fly. The legs are also preserved but the wings are missing. The head has very good detail. The slab has two Tipula sp. on the back.
The Asilidae are the robber fly family, also called assassin flies. They are powerfully built, bristly flies with a short, stout proboscis enclosing the sharp, sucking hypopharynx. The name robber flies reflects their notoriously aggressive predatory habits; they feed mainly or exclusively on other insects and as a rule they wait in ambush and catch their prey in flight.