Hammertail
Guides
Efferia argentifrons
Silver-faced Hammertail
Efferia argentifrons is a robber fly in the family Asilidae, first described by Hine in 1911. The species is characterized by its distinctive silvery facial markings, as indicated by its specific epithet ('argentifrons' = silver-faced). It belongs to a large genus of predatory flies known for their robust build and aggressive hunting behavior. Field observations of this species are sparse, with only three documented observations on iNaturalist, suggesting it may be uncommon or underreported.
Efferia completa
Rio Grande Hammertail
Efferia completa is a species of robber fly (family Asilidae) known by the common name Rio Grande Hammertail. It belongs to the large and diverse genus Efferia, which comprises predatory flies distributed primarily in the Americas. The species was described by Macquart in 1838. Like other asilids, it is presumed to be an aerial predator of other insects.
Efferia cuervana
Red-legged Hammertail
Efferia cuervana is a species of robber fly in the family Asilidae, first described by Hardy in 1943. It belongs to the large genus Efferia, which contains numerous species distributed primarily in the Americas. Robber flies in this genus are predatory insects known for their robust build, large compound eyes, and characteristic perching behavior while hunting. The common name 'Red-legged Hammertail' refers to distinctive morphological features of this species.
Efferia davisi
Davis Hammertail
Efferia davisi is a species of robber fly in the family Asilidae, first described by Wilcox in 1966. It belongs to a large genus of predatory flies commonly known as 'hammertails' due to the swollen male genital capsule. The species is part of the diverse Nearctic fauna of Efferia, which contains numerous species distributed across North America. Like other robber flies, E. davisi is an aerial predator that captures other insects in flight.
Efferia helenae
Helen Hammertail
Efferia helenae is a species of robber fly in the family Asilidae, first described by Bromley in 1951. The species is known from limited observations, with only 14 documented occurrences on iNaturalist. Like other members of the genus Efferia, it is presumed to be a predatory fly that hunts other insects. The common name "Helen Hammertail" refers to the characteristic swollen genital capsule of males in this genus.
Efferia texana
Texas Hammertail
Efferia texana is a species of robber fly in the family Asilidae, commonly known as the Texas Hammertail. This predatory fly is native to southwestern North America and belongs to a diverse genus of aerial predators that hunt other insects. The species was first described by Banks in 1919 and is recognized as a valid taxon in major databases including GBIF and Catalogue of Life.
Efferia wilcoxi
Wilcox Hammertail
Efferia wilcoxi is a species of robber fly in the family Asilidae, described by Bromley in 1940. The species belongs to the genus Efferia, a large and diverse group of predatory flies commonly known as "hammertails" due to the swollen genital capsule in males. As a member of the subfamily Dasypogoninae, this species exhibits the characteristic predatory behavior and morphology typical of robber flies, including large compound eyes, a concave face with a mystax of bristles, and raptorial legs adapted for capturing prey in flight. The specific epithet "wilcoxi" honors an individual, likely an entomologist or collector associated with the type specimen.