Efferia bicaudata

Efferia bicaudata is a species of robber fly in the family Asilidae, commonly known as the Great Plains Hammertail. The species was originally described as Erax bicaudatus by Hine in 1919 and later transferred to the genus Efferia. A 1964 study in the Annals of the Entomological Society of America examined its distribution, ethology, and egg morphology, representing one of the few detailed biological studies of this species. As a member of the Asilidae, it is a predatory fly that captures other insects in flight.