Asilidae
Guides
Efferia cressoni
Efferia cressoni is a species of robber fly in the family Asilidae, originally described by Hine in 1919. The species belongs to a large and diverse genus of predatory flies found primarily in the Americas. Robber flies in the genus Efferia are known for their robust build, strong flying ability, and predatory behavior. The specific epithet honors Cresson, likely referring to the entomologist Ezra Townsend Cresson.
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 duncani
Efferia duncani is a species of robber fly in the family Asilidae, first described by Wilcox in 1966. The genus Efferia comprises large, predatory flies that are morphologically similar to the related genus Triorla. Robber flies in this group are characterized by their robust build, large eyes, and predatory behavior. Specific ecological details for E. duncani remain poorly documented in the available literature.
Efferia femorata
Pine-trunk Hammertail
A species of robber fly in the family Asilidae, commonly known as the Pine-trunk Hammertail. The species was described by Macquart in 1838 and belongs to the diverse genus Efferia, which contains numerous similar-looking species that are often difficult to distinguish without careful examination.
Efferia frewingi
Columbia River Hammertail
Efferia frewingi is a species of robber fly (family Asilidae) described by Wilcox in 1966. Based on the genus Efferia, it belongs to a diverse group of predatory flies known for their robust bodies, large eyes, and aerial hunting behavior. The species epithet "frewingi" honors an individual, following the patronymic naming convention common in entomology. The common name "Columbia River Hammertail" suggests an association with the Columbia River region, though specific ecological details remain poorly documented in accessible literature.
Efferia gila
Efferia gila is a species of robber fly in the family Asilidae, described by Wilcox in 1966. The genus Efferia comprises predatory flies commonly known as robber flies, characterized by their stout bodies, large eyes, and predatory behavior. This species is part of a diverse genus distributed primarily in the Americas.
Efferia grandis
Great Mesquite Hammertail
Efferia grandis is a species of robber fly (family Asilidae) described by Hine in 1919. It belongs to the diverse genus Efferia, which contains many species of predatory flies found primarily in North America. The common name "Great Mesquite Hammertail" suggests an association with mesquite habitats, though specific ecological details remain limited in available sources.
Efferia harveyi
Harvey Hammertail
Efferia harveyi is a species of assassin fly (family Asilidae), commonly known as the Harvey Hammertail. Originally described as Erax harveyi by Hine in 1919, it was later transferred to the genus Efferia. Like other members of the Asilidae, this species is a predatory fly. The common name 'Harvey Hammertail' refers to the clubbed or expanded abdomen tip characteristic of many Efferia species. The species has been documented in at least 25 observations on iNaturalist.
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 kansensis
Efferia kansensis is a species of robber fly in the family Asilidae, described by Hine in 1919. The specific epithet "kansensis" indicates Kansas as the type locality. As a member of the genus Efferia, it belongs to a group of medium to large-sized robber flies that are characteristic of North American arid and semi-arid regions. The genus Efferia is taxonomically complex and has undergone significant revision, with some former segregates now recognized as valid genera.
Efferia kondratieffi
Kondratieff Hammertail
Efferia kondratieffi is a species of robber fly in the family Asilidae, described by Bullington & Lavigne in 1984. It belongs to the large genus Efferia, which comprises numerous species across North and South America. The species was formally described with comparative notes on the related Efferia aestuans. Like other robber flies, it is a predatory insect with a characteristic robust build and strong flying ability.
Efferia latruncula
Efferia latruncula is a species of robber fly in the family Asilidae, first described by Williston in 1885. It belongs to the large genus Efferia, which contains numerous species distributed primarily in arid and semi-arid regions of North and South America. Like other robber flies, it is a predatory insect that captures other arthropods in flight. The specific epithet 'latruncula' is Latin for 'little robber' or 'brigand,' reflecting the predatory habits characteristic of the family.
Efferia leucocoma
Efferia leucocoma is a species of robber fly in the family Asilidae. Robber flies are predatory insects known for their aggressive hunting behavior, capturing other insects in flight. Members of the genus Efferia are generally robust, medium to large-sized flies with characteristic morphological features including a well-developed mystax (beard of bristles on the face). The specific epithet 'leucocoma' refers to white hair-like structures, likely describing some aspect of the species' pubescence or coloration.
Efferia mesquite
Mesquite robber fly
Efferia mesquite is a species of robber fly in the family Asilidae, described by Bromley in 1951. The species epithet "mesquite" suggests an association with mesquite trees (Prosopis spp.), which serve as perching and hunting substrates for adults. Like other Efferia species, it is a predatory fly that captures other insects in flight. The genus Efferia is part of a complex of robber flies formerly grouped under Efferia but now split into several genera including Efferia sensu stricto and Triorla.
Efferia monki
Efferia monki is a species of robber fly in the family Asilidae, described by Bromley in 1951. Like other members of the genus Efferia, it belongs to a diverse group of predatory flies characterized by their stout bodies, large compound eyes, and raptorial legs adapted for capturing prey in flight. The species name honors an individual with the surname Monk, though the specific etymology is not detailed in available sources. As with most Efferia species, detailed biological information remains limited in published literature.
Efferia mortensoni
Portal Hammertail
Efferia mortensoni is a species of robber fly in the family Asilidae, described by Wilcox in 1966. It is known by the common name "Portal Hammertail." Like other members of the genus Efferia, this species is a predatory dipteran that likely hunts other insects. The species name suggests a connection to the Portal area in southeastern Arizona, a region well-known among entomologists for its exceptional biodiversity. Robber flies in this genus are typically active during daylight hours and are often observed perching on vegetation or the ground while hunting.
Efferia nemoralis
Woodland Hammertail
Efferia nemoralis is a species of robber fly in the family Asilidae, commonly known as the Woodland Hammertail. It is one of approximately 80 species in the genus Efferia, which is distributed primarily in the Americas. The species was originally described as Erax nemoralis by Hine in 1911 and later transferred to Efferia. Like other robber flies, it is a predatory insect that captures prey in flight.
Efferia neoinflata
Efferia neoinflata is a species of robber fly (family Asilidae) described by Wilcox in 1966. It belongs to a diverse genus of predatory flies distributed primarily in the Americas. The species epithet "neoinflata" suggests a relationship to or distinction from E. inflata, a pattern common in Efferia species nomenclature. As with other robber flies, adults are aerial predators that capture other insects in flight. The genus Efferia was historically treated as a subgenus within a broader concept of Asilus but has been elevated to full generic status in modern classifications.
Efferia ordwayae
Efferia ordwayae is a species of robber fly (family Asilidae) described by Wilcox in 1966. Like other members of the genus Efferia, it is a predatory dipteran characterized by a robust body, strong legs adapted for seizing prey, and a prominent mystax of bristles on the face. The genus Efferia is one of the largest genera of robber flies in North America, with species typically associated with open, dry habitats. Specific information about the biology and distribution of E. ordwayae remains limited in the available literature.
Efferia pallidula
Efferia pallidula is a species of robber fly in the family Asilidae, described by Hine in 1911. As a member of the large and diverse genus Efferia, it shares the characteristic predatory habits and robust morphology typical of this group. The specific epithet "pallidula" suggests pale coloration relative to congeners. Detailed natural history information for this particular species appears limited in the available literature.
Efferia pernicis
Efferia pernicis is a species of robber fly in the family Asilidae, described by Coquillett in 1893. As a member of the genus Efferia, it belongs to a diverse group of predatory flies characterized by their robust build, large eyes, and raptorial legs adapted for capturing prey in flight. The species is part of the Asilinae subfamily, which contains many of the larger and more conspicuous robber flies in North America.
Efferia pinali
Efferia pinali is a species of robber fly (family Asilidae) described by Wilcox in 1966. As a member of the genus Efferia, it belongs to a diverse group of predatory flies found primarily in the Americas. The specific epithet "pinali" suggests an association with pine habitats or the Pinal region, though explicit habitat documentation for this particular species is limited. Robber flies in this genus are generally medium to large-sized predators that hunt other insects in flight.
Efferia pogonias
Yellow-bearded Hammertail
Efferia pogonias is a species of robber fly in the family Asilidae, commonly known as the yellow-bearded hammertail. It is endemic to the eastern United States, where it occurs from Maine to Georgia and westward to Minnesota and Texas. The species prefers open, dry habitats including sandy inland locations. Adults are active from May to October with peak activity in September and October. Females oviposit in soil.
Efferia prairiensis
Prairie Hammertail
Efferia prairiensis is a species of robber fly in the family Asilidae, commonly known as the Prairie Hammertail. It belongs to the large and diverse genus Efferia, which contains many North American species. Robber flies in this genus are predatory insects that typically hunt other insects in flight. The specific epithet "prairiensis" suggests an association with prairie habitats.
Efferia prattii
Laredo Hammertail
Efferia prattii is a species of robber fly in the family Asilidae, originally described by Hine in 1919. The species is known from the southern United States, particularly Texas, and is referred to by the common name "Laredo Hammertail." As a member of the genus Efferia, it belongs to a group of large, predatory flies that are active hunters of other insects. The species has been documented in entomological surveys in western Texas, where it was observed at mercury-vapor lights in juniper chaparral habitat alongside other asilid species.
Efferia producta
White Thorny Hammertail
Efferia producta is a robber fly species in the family Asilidae, described by Hine in 1919. The common name "White Thorny Hammertail" refers to distinctive features of this species. As with other Efferia species, it belongs to a diverse genus of predatory flies known for their robust build and predatory habits. The species has been documented through limited observations on iNaturalist, suggesting it may be relatively uncommon or underreported. Robber flies in this genus are typically associated with arid and semi-arid habitats in western North America.
Efferia rapax
Yellow-haired Hammertail
Efferia rapax is a species of robber fly in the family Asilidae, commonly known as the Yellow-haired Hammertail. Robber flies in this genus are predatory insects known for their aggressive hunting behavior, capturing other insects in flight. The species is part of a large and diverse genus of medium to large-sized robber flies distributed primarily in the New World. Specific biological details for E. rapax are limited in published literature.
Efferia slossonae
Scrub Hammertail
Efferia slossonae is a species of robber fly (family Asilidae) described by Hine in 1919. It belongs to the diverse genus Efferia, a group of predatory flies distributed primarily in the Americas. The species has been documented in the southwestern United States, with observations concentrated in Texas and surrounding regions. Like other robber flies, it is an aerial predator that captures other insects in flight.
Efferia spiniventris
Efferia spiniventris is a species of robber fly (family Asilidae) described by Hine in 1919. The species belongs to the large and diverse genus Efferia, which is primarily distributed in the New World. Robber flies in this genus are predatory as adults, typically hunting other insects. The specific epithet "spiniventris" refers to spiny ventral characteristics. The genus Efferia has undergone taxonomic revision, with some former subgenera now recognized as distinct genera such as Triorla.
Efferia staminea
Straw-faced Hammertail
Efferia staminea is a species of robber fly in the family Asilidae. It has been studied for its predatory behavior, with research documenting how its diet varies temporally and spatially in response to prey availability. The species exhibits opportunistic feeding patterns, shifting prey composition based on local prey abundance—including documented increases in ant predation during mating swarms of Formica subpolita. It serves as a generalist predator in grassland ecosystems.
Efferia subarida
Tucson Hammertail
Efferia subarida is a robber fly species in the family Asilidae, first described by Bromley in 1940. It is commonly known as the Tucson Hammertail and is found in the southwestern United States, particularly Arizona. The species belongs to the diverse genus Efferia, which contains many large, predatory flies characterized by their stout bodies, prominent compound eyes, and powerful flight capabilities. Like other robber flies, E. subarida is an active aerial predator that captures other insects in flight.
Efferia subcuprea
Chiricahua Hammertail
Efferia subcuprea is a species of robber fly (family Asilidae) described by Schäffer in 1916. The species belongs to the genus Efferia, a large and diverse group of predatory flies distributed primarily in the New World. The common name "Chiricahua Hammertail" suggests an association with the Chiricahua region of southeastern Arizona. Robber flies in this genus are generally characterized by their robust build, strong predatory habits, and often distinctive sexual dimorphism, with males typically possessing a swollen terminal abdominal segment.
Efferia subpilosa
Efferia subpilosa is a species of robber fly in the family Asilidae, first described by Schäffer in 1916. The genus Efferia comprises medium to large-sized predatory flies distributed primarily in the New World, with many species occurring in arid and semi-arid regions of North and South America. Members of this genus are characterized by their robust build, prominent compound eyes, and predatory habits. Efferia subpilosa is one of numerous species within this diverse genus, though specific ecological and behavioral details remain poorly documented in the available literature.
Efferia tabescens
Sesqui Hammertail
Efferia tabescens is a species of robber fly (family Asilidae) described by Nathan Banks in 1919. The common name "Sesqui Hammertail" refers to this species. Robber flies in the genus Efferia are predatory insects that capture other insects in flight. The species has been documented through 143 iNaturalist observations, indicating it is moderately well-recorded in citizen science databases. As a member of the Asilidae, it shares the family's characteristic predatory behavior and robust body form adapted for aerial hunting.
Efferia tagax
Arizona Club-legged Hammertail
Efferia tagax is a robber fly species in the family Asilidae, first described by Williston in 1885. It occurs in the southwestern United States, particularly Arizona, where it has been recorded at mercury-vapor lights in juniper chaparral habitat. The species belongs to a diverse genus of predatory flies commonly known as club-legged hammertails. Like other Efferia species, it likely exhibits typical robber fly predatory behavior, ambushing and capturing other insects in flight.
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 tolandi
Efferia tolandi is a species of robber fly (family Asilidae) described by Wilcox in 1966. The genus Efferia comprises medium to large-sized predatory flies found primarily in arid and semi-arid regions of North America. Members of this genus are characterized by their robust build, large compound eyes, and predatory habits. Efferia species are often encountered at light traps and are active predators of other insects.
Efferia tricella
Silver Hammertail
Efferia tricella is a species of robber fly in the family Asilidae, commonly known as the Silver Hammertail. Robber flies in the genus Efferia are predatory insects known for their robust build, large eyes, and aggressive hunting behavior. The species was described by Bromley in 1951. Like other Asilidae, it is presumed to be an aerial predator that captures other insects in flight.
Efferia triton
Triton Hammertail
Efferia triton is a species of robber fly in the family Asilidae, commonly known as the Triton Hammertail. Like other robber flies, it is an aerial predator that captures prey in flight. The species belongs to the large and diverse genus Efferia, which contains numerous species across North America. Specific ecological details for E. triton remain limited in published sources.
Efferia tuberculata
Thorny Hammertail
Efferia tuberculata is a species of robber fly in the family Asilidae, commonly known as the Thorny Hammertail. The species was described by Coquillett in 1904. Robber flies in the genus Efferia are predatory insects known for their robust build and distinctive genital structures in males. Like other Asilidae, they are aerial predators that capture other insects in flight.
Efferia tucsoni
Reddish Thorny Hammertail
Efferia tucsoni is a species of robber fly (family Asilidae) described by Wilcox in 1966. The common name 'Reddish Thorny Hammertail' refers to distinctive morphological features typical of the genus. Robber flies in the genus Efferia are predatory dipterans known for their aggressive hunting behavior and distinctive genital capsule morphology in males. The species is part of a large North American genus that has undergone taxonomic revision, with some former Efferia species now placed in related genera such as Triorla.
Efferia varipes
Colorado Hammertail
Efferia varipes is a species of robber fly in the family Asilidae, commonly known as the Colorado Hammertail. The species belongs to the large and diverse genus Efferia, which contains numerous species across North and South America. Robber flies in this genus are predatory insects that capture other insects in flight. The specific epithet 'varipes' refers to variable legs, suggesting some morphological variation in this character.
Efferia vertebrata
Mountain Hammertail
Efferia vertebrata is a species of robber fly (family Asilidae) first described by Bromley in 1940. Known by the common name "Mountain Hammertail," this predatory dipteran belongs to the large and diverse genus Efferia, which contains numerous species distributed primarily in the Americas. Robber flies in this genus are characterized by their robust build, strong flying ability, and predatory habits. The specific epithet "vertebrata" likely refers to some aspect of the species' structural morphology, though the precise meaning is not documented in readily available sources.
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.
Efferia willistoni
Williston Hammertail
Efferia willistoni is a species of robber fly in the family Asilidae, commonly known as the Williston Hammertail. It is one of approximately 200 species in the genus Efferia, a diverse group of predatory flies distributed primarily in the Americas. The species was described by Hine in 1919. As with other asilids, it is presumed to be an active aerial predator of other insects.
Efferia yuma
Efferia yuma is a species of robber fly in the family Asilidae, described by Wilcox in 1966. Robber flies in the genus Efferia are among the largest and most charismatic members of the family, often recognized by their impressive size, striking green eyes in males, and predatory habits. The species name "yuma" likely refers to the Yuma region of southwestern Arizona or adjacent California, suggesting an association with arid southwestern habitats. Members of this genus are aerial predators that capture other insects in flight.
Efferia zonata
Banded Hammertail
Efferia zonata is a species of robber fly (family Asilidae) described by Hine in 1919. The species belongs to the Efferia group, a lineage of large, predatory flies formerly treated as a subgenus of Efferia but now widely regarded as comprising valid related genera including Triorla. As a member of this group, E. zonata likely shares characteristics with other large, powerful predatory flies that actively hunt other insects. The specific epithet 'zonata' suggests banded coloration patterning.
Eucyrtopogon calcaratus
Eucyrtopogon calcaratus is a species of robber fly in the family Asilidae, described by Curran in 1923. It belongs to a genus of predatory flies known for their aerial hunting behavior. The specific epithet "calcaratus" refers to a spur or calcar, likely describing a morphological feature of the legs. The species is part of the diverse robber fly fauna of North America, though detailed biological information appears limited in available sources.
Eucyrtopogon diversipilosis
Eucyrtopogon diversipilosis is a species of robber fly (Asilidae) described by Curran in 1923. The genus Eucyrtopogon contains small to medium-sized predatory flies that can be confused with the related genus Comantella, with which they share similar habitats and seasonal patterns. Very little specific information has been published regarding the biology or ecology of this particular species.
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