Aquatic-larvae
Guides
Anasimyia
swamp flies
Anasimyia is a genus of wetland hoverflies (Syrphidae) characterized by aquatic larval development. The genus was historically treated as a subgenus of Lejops but has been elevated to full generic status based on morphological and molecular evidence. Adults are associated with marshy and aquatic habitats. The genus includes approximately 20 described species distributed primarily across the Holarctic region.
Anasimyia chrysostoma
Lump-legged Swamp Fly
Anasimyia chrysostoma, commonly known as the lump-legged swamp fly, is a syrphid fly species distributed across the United States and Canada. Adults are flower visitors that feed on nectar and pollen. The larvae are aquatic and possess the characteristic rat-tailed morphology typical of the genus Anasimyia. The species is considered fairly common and has been documented in 355 observations on iNaturalist.
Anasimyia distincta
short-spurred swamp fly
Anasimyia distincta, known as the short-spurred swamp fly, is a rare syrphid fly species documented in the northeastern United States and adjacent Canada. Adults are commonly observed on flowers where they feed on nectar and pollen. The species belongs to a genus whose larvae are aquatic and possess the characteristic rat-tailed morphology of eristaline hoverflies.
Antocha
Antocha is a genus of crane flies (Limoniidae) comprising approximately 161 species across three subgenera. The genus is globally distributed with highest diversity in the Oriental (83 species) and East Palearctic (53 species) regions. Larvae are aquatic and rheophilic, inhabiting fast-flowing streams and rivers where they construct silken tubes on submerged rocks. The genus exhibits notable sensitivity to hydrological disturbances, making it a potential indicator of stream ecosystem health.
Atrichopogon peregrinus
biting midge
Atrichopogon peregrinus is a species of biting midge in the family Ceratopogonidae. The specific epithet "peregrinus" (Latin for "wanderer" or "foreigner") suggests a potentially wide-ranging or introduced distribution, though detailed geographic records remain limited. As a member of the genus Atrichopogon, it belongs to a diverse group of small, blood-feeding flies commonly known as no-see-ums or punkies. The species was described by Johannsen in 1908, indicating it has been recognized in scientific literature for over a century, though comprehensive biological studies appear sparse.
Bellura
Bellura is a genus of moths in the family Noctuidae, established by Walker in 1865. The genus contains approximately eight described species distributed in North America. Caterpillars of at least some species are aquatic or semi-aquatic, feeding on aquatic plants such as water lilies. The genus is notable among Noctuidae for this aquatic larval ecology, which is relatively uncommon in the family.
Bezzia perplexa
Bezzia perplexa is a species of biting midge in the family Ceratopogonidae, described by Dow and Turner in 1976. The genus Bezzia comprises non-blood-feeding ceratopogonids whose larvae develop in aquatic or semi-aquatic habitats. As a member of the Palpomyiini tribe, this species shares characteristics with other predatory or detritivorous biting midges. Published records for this species are limited.
Bittacomorpha occidentalis
Western Phantom Crane Fly
Bittacomorpha occidentalis is a species of phantom crane fly in the family Ptychopteridae. This dipteran belongs to a group known for their distinctive hovering flight behavior and elongated legs. The species was described by Aldrich in 1895. Like other members of the genus Bittacomorpha, adults are characterized by their striking black-and-white banded legs and unique flight pattern where they appear to drift with legs extended. The larvae develop in aquatic or semi-aquatic environments, typical for the family.
Chrysogaster
Low-horned Wrinkleheads
Chrysogaster is a genus of small hoverflies in the subfamily Eristalinae. Adults are dark or black with shiny colorful reflections and visit flowers in damp marshy areas. The aquatic larvae possess a short posterior breathing siphon, shorter than that of related genera such as Eristalis. Several related genera—Melanogaster, Orthonevra, Lejogaster, and Riponnensia—were formerly classified within Chrysogaster.
Chrysops dacne
Chrysops dacne is a species of deer fly in the family Tabanidae, described by Philip in 1955. The species name is a playful reference, sounding like 'balls of fire' when pronounced. Like other members of the genus Chrysops, it is likely a biting fly with aquatic or semi-aquatic larval stages, though specific details about this particular species remain poorly documented in available literature.
Chrysops nigripes
Chrysops nigripes is a species of deer fly in the family Tabanidae, first described by Zetterstedt in 1838. Larval development has been documented in subarctic peatland environments, where the species occupies aquatic to semi-aquatic microhabitats. Life cycle completion at subarctic latitudes may require 7–8 years, indicating exceptionally slow growth rates compared to temperate populations of related species.
Culicidae
mosquitoes, mosquito
Culicidae, commonly known as mosquitoes, is a family of small flies in the order Diptera. Females of most species are ectoparasites that feed on vertebrate blood using specialized piercing-sucking mouthparts, while males feed exclusively on plant nectar and other sugar sources. The family includes thousands of species distributed worldwide, with many serving as vectors for significant human and animal diseases including malaria, yellow fever, dengue, and West Nile virus. Mosquitoes require standing water to complete their aquatic larval and pupal stages.
Dicranota
Dicranota is a genus of crane flies (Diptera: Pediciidae) established by Zetterstedt in 1838. The genus contains multiple subgenera, including Eudicranota and Rhaphidolabis. Species occur across the Northern Hemisphere, with documented records from Europe, Korea, the Caucasus, and Central Asia. Larvae are aquatic and predatory, inhabiting cold, clean streams and springs.
Elophila nebulosalis
Nebulous Munroessa Moth
Elophila nebulosalis is a moth species in the family Crambidae, described by Charles H. Fernald in 1887. It is restricted to the southeastern United States, with records from South Carolina to Florida. The larvae are thought to be aquatic, consistent with other members of the subfamily Acentropinae.
Eristalinae
Drone Flies and Allies
Eristalinae is a subfamily of hoverflies (Syrphidae) comprising approximately nine tribes and notable for exceptional Batesian mimicry of bees and wasps. Adults are important pollinators, while larvae exhibit the greatest habitat diversity among hoverflies, occupying aquatic environments, decaying organic matter, sap runs, and even wasp nests. The subfamily includes the well-known drone fly (Eristalis tenax), whose larvae—called rat-tailed maggots—possess an extendable posterior breathing siphon.
Eristalini
Rat-tail Maggot Flies
Eristalini is a tribe of hoverflies (Syrphidae) characterized by larvae known as "rat-tailed maggots," which possess a posterior telescopic breathing siphon. Several species are notable hymenopteran mimics: Eristalis species resemble honeybees, while Helophilus and Parhelophilus display wasp-like yellow and black striping. Adults function as pollinators, while larvae inhabit aquatic or semi-aquatic environments rich in decaying organic matter.
Eristalinus
Lagoon Flies
Eristalinus is a genus of hoverflies (family Syrphidae) characterized by distinctive spotted or banded eye patterns in most species. These stout, nimble fliers are distributed across Europe, Africa, Asia, and the Americas, with several species becoming widespread invasives outside their native ranges. The genus has undergone taxonomic revision, with molecular and morphological studies reorganizing former subgenera Eristalodes and Lathyrophthalmus into two primary clades. Species such as E. taeniops and E. aeneus are notable for their rapid global spread and potential as managed pollinators in agricultural systems.
Eristalinus aeneus
Common Lagoon Fly
Eristalinus aeneus is a hoverfly (Syrphidae) with subcosmopolitan distribution, commonly found in freshwater habitats including coastal lagoons, ponds, and slow-moving rivers. Adults are effective pollinators of crops including watermelon and mango, and have been evaluated as managed pollinators in protected agriculture. The species exhibits distinctive patterned eyes with black spots, metallic coloration, and rapid hovering flight. Larvae develop in aquatic or semi-aquatic environments with decaying organic matter, possessing a characteristic extensible breathing siphon.
Eristalis
Drone Flies, Droneflies
Eristalis is a large genus of hoverflies (family Syrphidae) comprising approximately 99 species. Adults are commonly called drone flies due to their resemblance to honeybee drones, a form of Batesian mimicry that provides protection from predators. The larvae, known as rat-tailed maggots, are aquatic and possess an extendable breathing siphon that allows them to inhabit oxygen-depleted environments such as stagnant water, sewage, and decomposing organic matter. Adults are important generalist pollinators, with some species proposed as managed alternatives to honey bees for agricultural pollination.
Eristalis brousii
Hourglass Drone Fly
Eristalis brousii, commonly known as the hourglass drone fly, is a hoverfly species first described by Samuel Wendell Williston in 1882. The species has experienced severe population decline across North America following the introduction of the European congener Eristalis arbustorum near Toronto around 1885. As of 2019, it persists only along the lake margin of Hudson Bay in Northern Canada, making it one of the most geographically restricted hoverflies on the continent. Like other Eristalis species, adults are pollinators while larvae develop as aquatic filter-feeders.
Eristalis flavipes
orange-legged drone fly
Eristalis flavipes, commonly known as the orange-legged drone fly, is a North American hoverfly in the family Syrphidae. Adults are striking mimics of bumblebees, measuring 13–17 mm in length, with abundant bright yellow pile on a black body and distinctive orange-red legs. The species is active from early April through mid-October, occurring across diverse habitats with particular affinity for wetlands. Adults visit flowers for nectar and pollen, while larvae are aquatic rat-tailed maggots that filter-feed in standing water.
Eristalis fratercula
Eristalis fratercula is a species of drone fly in the family Syrphidae, described by McNeill. It belongs to a genus of hoverflies known for Batesian mimicry of bees and wasps. The species is listed in grasshopper survey records from Colorado and Wyoming, suggesting it occurs in western North American grasslands. Like other Eristalis species, adults are likely pollinators and larvae develop in aquatic or semi-aquatic organic-rich habitats.
Eristalis rupium
Spot-winged Drone Fly
Eristalis rupium, the spot-winged drone fly, is a European hoverfly species first described by Fabricius in 1805. It is a common species across Europe and uncommon in North America. Like other Eristalis species, it exhibits Batesian mimicry of honey bees and serves as an important pollinator. The larvae are aquatic filter-feeders of the rat-tailed type, inhabiting clear-water streams.
Eulichadidae
Forest Stream Beetles
Eulichadidae is a small family of beetles within Elateriformia, comprising two extant genera with contrasting distributions: Eulichas (Indomalayan realm, Asia) and Stenocolus (Western North America). Adults are terrestrial, while larvae are obligately aquatic in forest streams. The family exhibits notable ecological divergence between genera in habitat use and adult behavior.
Eurimyia
rat-tail maggot flies, swamp flies
Eurimyia is a genus of hoverflies (family Syrphidae) containing three described species. These flies are commonly known as rat-tail maggot flies due to the distinctive elongated breathing tube of their aquatic larvae. The genus was established by Bigot in 1883 and previously included species now classified under Lejops. Adults are associated with wetland habitats.
Hedriodiscus leucogaster
Hedriodiscus leucogaster is a species of soldier fly in the family Stratiomyidae, described by James in 1933. The genus Hedriodiscus is closely related to Psellidotus; these two genera are readily distinguishable in the Nearctic region but their distinction becomes less clear in the Neotropics, particularly in South America. Most species in both genera are poorly known beyond their original descriptions. Larvae of the subfamily Stratiomyinae are aquatic, and adults of this subfamily often exhibit patterned eyes with horizontal banding, suggesting an ability to detect horizontally polarized light.
Hedriodiscus varipes
Hedriodiscus varipes is a species of soldier fly in the family Stratiomyidae. The genus Hedriodiscus belongs to the subfamily Stratiomyinae, whose larvae are known to be aquatic. Adults of related species in this subfamily exhibit patterned eyes with horizontal banding, suggesting an ability to detect horizontally polarized light. The species is distributed in Canada and the United States.
Helophilina
rat-tail maggot flies
Helophilina is a subtribe of hoverflies within the family Syrphidae, commonly referred to as rat-tail maggot flies. The subtribe encompasses approximately 19 genera and over 180 described species. Members are classified within the subfamily Eristalinae and tribe Eristalini. The common name derives from the aquatic or semi-aquatic larval stage, which possesses a long, telescopic breathing siphon resembling a rat's tail.
Helophilus
Marsh Flies, Tiger Hoverflies
Helophilus is a genus of moderate to large hoverflies in the family Syrphidae, commonly known as marsh flies or tiger hoverflies. Adults are notable bee or wasp mimics with distinctive lengthwise yellow stripes on the thorax and transverse bands on the abdomen. Larvae are aquatic "rat-tailed maggots" that filter-feed on microorganisms in organic-rich water. The genus comprises two subgenera: Helophilus and Pilinasica (the latter containing endemic New Zealand species).
Helophilus bottnicus
Gray-banded Marsh Fly
Helophilus bottnicus is a hoverfly in the family Syrphidae, commonly known as the Gray-banded Marsh Fly. It belongs to a genus whose larvae are aquatic, developing in decaying organic matter submerged in water. Adults are sun-loving and often exhibit yellowjacket mimicry with characteristic thoracic striping. The species was described by Wahlberg in 1844 and is recorded from Norway and Sweden.
Helophilus intentus
Yellow-legged Marsh Fly
Helophilus intentus is a species of syrphid fly (flower fly) in the family Syrphidae. It belongs to the genus Helophilus, whose members are commonly known as marsh flies due to their association with aquatic habitats. The larvae develop in decaying plant matter submerged in water. Adults are sun-loving and frequently observed visiting flowers for nectar and pollen.
Helophilus latifrons
Broad-headed Marsh Fly
Helophilus latifrons, commonly known as the Broad-headed Marsh Fly, is a species of syrphid fly in the family Syrphidae. Adults are flower visitors that obtain nectar and pollen from blossoms. The larvae are aquatic and develop in decaying submerged vegetation, functioning as decomposers in wetland ecosystems. The species occurs across much of North America including the United States, southern Canada, and mountainous regions of Mexico.
Helophilus neoaffinis
Northwestern Marsh Fly
A syrphid fly species in the genus Helophilus, recognized by iNaturalist as the Northwestern Marsh Fly. As with other members of its genus, it likely exhibits yellowjacket mimicry with vertical yellow stripes on the thorax. The larvae develop in decaying plant matter submerged in water, characteristic of the 'rat-tailed maggot' form found in aquatic or semi-aquatic habitats.
Hoplitimyia
Hoplitimyia is a genus of soldier flies (family Stratiomyidae) established by James in 1934. The genus comprises approximately ten described species distributed across the Americas, with records from both North and South America. Species within this genus exhibit the characteristic features of the subfamily Stratiomyinae, including patterned eyes and wasp-mimicking coloration. Larvae are aquatic, a trait common to the subfamily.
Hoplitimyia constans
Hoplitimyia constans is a species of soldier fly in the family Stratiomyidae, distributed in the United States. The genus Hoplitimyia includes species with aquatic larvae and adults that often exhibit wasp-mimicking coloration and behavior. Members of this genus are known for their flighty behavior and attraction to flowers. The specific epithet "constans" was established by Loew in 1872, originally described under the genus Stratiomyia.
Hoplitimyia sp-near-mutabilis
A wasp-mimicking soldier fly in the family Stratiomyidae, originally misidentified as a vespid wasp due to its black and yellow coloration and flight behavior. The species exhibits striking, sexually dimorphic eye patterns and has aquatic larvae. Adults are highly active and reluctant to settle, making observation and photography challenging. The specimen discussed was collected in Buenos Aires Province, Argentina, and identified by dipterist Martin Hauser as likely belonging to the genus Hoplitimyia, possibly near H. mutabilis, though species boundaries in this group remain unresolved.
Hoplitimyia subalba
Hoplitimyia subalba is a species of soldier fly in the family Stratiomyidae, first described by Walker in 1854. The genus Hoplitimyia comprises species with aquatic larvae, and adults are known for their wasp-mimicking appearance and patterned compound eyes. This species occurs in South America, with records from the Brazilian states of Amazonas and Pará. Adults are reportedly flighty and difficult to photograph, exhibiting behavior consistent with nectar or pollen feeding when provided sugar solutions in captivity.
Langessa
black langessa moth
Langessa is a monotypic genus of crambid moths in the subfamily Acentropinae, established by Munroe in 1972. The sole species, Langessa nomophilalis (black langessa moth), occurs in the southeastern United States. Adults are small moths with distinctive bronzy-brown forewings and patterned hindwings. Larvae are aquatic, feeding on submerged vegetation.
Leptoconops californiensis
Leptoconops californiensis is a species of biting midge in the family Ceratopogonidae, first described by Wirth & Atchley in 1973. It belongs to the subgenus Brachyconops within the genus Leptoconops. The species is known from California, USA. Like other members of this genus, it is likely a blood-feeding pest with aquatic or semi-aquatic immature stages, though specific details about its biology remain poorly documented.
Libellula incesta
slaty skimmer
Libellula incesta, commonly known as the slaty skimmer, is a dragonfly species in the family Libellulidae native to eastern North America. Adults measure approximately 5.28 cm in length. The species exhibits pronounced sexual dimorphism in coloration: mature males are dark blue with black heads, while females and juveniles display brown abdomens with a darker dorsal stripe. Larvae are specialized inhabitants of lake benthos, and adults are active from June through August.
Limoniidae
Limoniid Crane Flies, Limoniidae, Short-palped Crane Flies
Limoniidae is the largest family of crane flies, comprising over 10,700 species in more than 150 genera. Members are distinguished from other crane flies primarily by their wing posture at rest: wings are typically held folded along the body rather than perpendicular to it. The family includes notable wingless snow flies in the genus Chionea, which are active in winter. Limoniids are generally smaller than other crane flies and occupy diverse habitats worldwide. Recent phylogenetic studies indicate the family is paraphyletic, with some limoniids more closely related to Tipulidae and Cylindrotomidae than to other limoniids.
Mallota
Mimic Flies
Mallota is a Holarctic genus of hoverflies (family Syrphidae) containing approximately 30 described species. Adults are well known for their robust, bee-like appearance, functioning as mimics of bumble bees (Bombus species). The genus has been documented from North America, Europe, and Asia. Larvae develop in water-filled tree holes and other decaying wood cavities.
Mallota bautias
Bare-eyed Bee-mimic Fly
Mallota bautias is a hoverfly (family Syrphidae) native to eastern North America. The species is notable for its exceptional mimicry of bumblebees (genus Bombus), particularly Bombus pennsylvanicus, serving as a classic example of Batesian mimicry in which a harmless species evolves to resemble a stinging model. Adult flies are pollinators, while larvae develop in tree holes filled with water. The species has been the subject of behavioral studies examining how avian predators respond to the mimic and its model.
Mallota diversipennis
A syrphid fly in the tribe Eristalini, described by Curran in 1922. Like other members of the genus Mallota, the larvae develop in water-filled tree holes. Adults are bumble bee mimics and are known to use leaves as platforms for grooming behavior. The specific epithet "diversipennis" refers to variation in wing pattern.
Mallota illinoensis
Midwestern Bee-mimic Fly
Mallota illinoensis is a syrphid fly (family Syrphidae) in the tribe Eristalini, described by Robertson in 1901 from Illinois. The species is a bumble bee mimic, with adults resembling bees in size, coloration, and behavior. Larvae develop in tree holes, where they inhabit water-collecting cavities in rotting wood. The species is part of a genus whose members are associated with aquatic or semi-aquatic larval habitats.
Mallota mississipensis
Eastern Mimic Fly
Mallota mississipensis is a species of hover fly (family Syrphidae) in the subfamily Eristalinae. It is one of approximately 13 species in the genus Mallota found in North America. The species is a bumble bee mimic, exhibiting the black and yellow coloration typical of this defensive mimicry strategy. Like other members of its genus, the larvae develop in aquatic or semi-aquatic environments, specifically in water that collects in tree holes. The species is known from eastern North America, with observations documented in the iNaturalist database.
Mallota posticata
Hairy-eyed Bee-mimic Fly
Mallota posticata is a syrphid fly (family Syrphidae) known for its bumble bee mimicry. The species is documented in Illinois and broader North America, with larvae developing in water-filled tree holes. Adults exhibit grooming behavior on leaves and serve as pollinators.
Mallota sackeni
brown-haltered mimic fly, brown-haltered bee-mimic fly
Mallota sackeni is a species of hover fly (family Syrphidae) native to western North America. The species is known for its bee-mimicry, a common defensive adaptation among syrphid flies. Adults are active pollinators, while larvae develop in aquatic or semi-aquatic environments typical of the tribe Eristalini. The species has been documented from British Columbia to southern California and eastward to Idaho and Utah.
Neoascia metallica
Double-banded Fen Fly
Neoascia metallica is a species of hoverfly (family Syrphidae) found across North America. Adults are commonly observed on flowers, where they feed on nectar and pollen. The species is known for its metallic coloration and association with wetland habitats. Larvae are aquatic, a trait that distinguishes this species from many other syrphid flies.
Neolimnophila placida
Placid Crane Fly
Neolimnophila placida is a crane fly species in the family Limoniidae, subfamily Chioneinae. It is widely distributed across the Holarctic region, occurring in both the Nearctic and Palaearctic realms. The species has been documented from northern North America through much of Europe and across northern Asia to Japan. Like other limoniid crane flies, it is associated with moist habitats where larvae develop in decaying organic matter.
Ochlerotatus punctor
Ochlerotatus punctor is a mosquito species in the family Culicidae, originally described from Europe but now recognized as having a broader distribution including North America. The species has been the subject of taxonomic study, with a notable record of a bilateral gynandromorph specimen from Germany. Like other members of the genus, it undergoes complete metamorphosis with aquatic larval stages.
Ochthera mantis
mantis fly, mantis shore fly
Ochthera mantis is a predatory shore fly in the family Ephydridae, first described by Charles De Geer in 1776. The species is notable for its raptorial forelegs, which are modified for seizing prey and resemble those of praying mantises—hence its common name. Both adults and larvae are predatory, with adults hunting small insects along shorelines and larvae feeding aquatically on midge and mosquito larvae. It is a Holarctic species with a limited distribution in Europe.
Odontomyia
soldier flies, brigadier flies
Odontomyia is a genus of soldier flies in the family Stratiomyidae. Species in this genus are characterized by distinctive color patterns, often with orange or yellow markings on dark backgrounds. The genus occurs across temperate and tropical regions of Europe, Asia, and the Americas. Larvae are aquatic, inhabiting ditches and other freshwater habitats. Some species serve as indicators of habitat quality in wetland ecosystems.
Odontomyia aldrichi
Odontomyia aldrichi is a species of soldier fly in the family Stratiomyidae, described by Johnson in 1895. The genus Odontomyia belongs to the tribe Stratiomyini within the subfamily Stratiomyinae. Members of this genus are characterized by their aquatic larval biology and adults often exhibit patterned eyes with horizontal banding. The species is part of a genus with primarily Nearctic distribution, though some species extend into the Neotropics.
Odontomyia cincta
Odontomyia cincta is a species of soldier fly in the family Stratiomyidae. The species is known from the United States and Canada, with distribution records from Vermont and other locations. As a member of the subfamily Stratiomyinae, its larvae are likely aquatic, a trait characteristic of this subfamily. Adults are recognized by features typical of the genus Odontomyia, including patterned eyes with horizontal banding that may facilitate detection of horizontally polarized light.
Odontomyia hoodiana
Odontomyia hoodiana is a species of soldier fly in the family Stratiomyidae, described by Bigot in 1887. The genus Odontomyia belongs to the subfamily Stratiomyinae, a group whose larvae are typically aquatic. As with many soldier flies, adults likely exhibit patterned eyes with horizontal banding, a trait common in this subfamily that has been linked to detection of horizontally polarized light. The species is known from North America (Canada, United States, and Mexico).
Odontomyia interrupta
Odontomyia interrupta is a species of soldier fly in the family Stratiomyidae. The genus Odontomyia belongs to the subfamily Stratiomyinae, whose larvae are known to be aquatic. Adults in this genus and related genera often exhibit patterned eyes with horizontal banding, which may function in detecting horizontally polarized light—potentially useful for locating mates and oviposition sites near water. The species occurs in North America, with records from the United States and Canada.
Odontomyia profuscata
Odontomyia profuscata is a species of soldier fly in the family Stratiomyidae, described by Steyskal in 1938. The genus Odontomyia belongs to the subfamily Stratiomyinae, a group whose larvae are aquatic. Adults in this genus often exhibit patterned eyes with horizontal banding, a trait associated with detection of horizontally polarized light. This species occurs in North America.
Odontomyia pubescens
Odontomyia pubescens is a species of soldier fly in the family Stratiomyidae, described by Day in 1882. The genus Odontomyia is part of the subfamily Stratiomyinae, whose larvae are known to be aquatic. Adults of related species often exhibit patterned eyes that may be adapted for detecting horizontally polarized light, a trait associated with aquatic lifestyles in insects. This species has been recorded from the United States and Canada.
Oreoleptidae
Oreoleptid Flies
Oreoleptidae is a monotypic family of flies established in 2005 based on the single species Oreoleptis torrenticola. The family was discovered in the Rocky Mountains where larvae inhabit torrential streams and groundwater wells. Adults were reared from larvae after decades of larval collections that could not be matched to any known adult stage. The family shows morphological affinities to both Pelecorhynchidae and Athericidae/Tabanidae, with distinctive male genitalia linking it to the latter group.
Oreoleptis torrenticola
Oreoleptis torrenticola is the sole species in the monotypic genus Oreoleptis and family Oreoleptidae, a family of flies established in 2005 based on this single species. The species was described from specimens collected in the Rocky Mountains, where its larvae inhabit torrential streams and have also been found in groundwater wells. This enigmatic dipteran represents a distinct lineage whose larval morphology shows similarities to Athericidae and Tabanidae but possesses distinctive abdominal prolegs.
Palpada
Plushback Flies
Palpada is a genus of 85 species of flower flies (hoverflies) in the tribe Eristalini, distributed across the Neotropical and Nearctic regions. Adults are often colorful and bee-like in appearance. The genus is distinguished from related Eristalini genera by specific morphological characters including uniform eye pile, pale hairs on the meron, and distinctive wing venation. Larvae are aquatic 'rat-tailed' maggots with extensible breathing siphons that allow survival in low-oxygen environments.
Palpada albifrons
White-faced Plushback
Palpada albifrons is a rare species of syrphid fly (hoverfly) characterized by its distinctive white-faced appearance and aquatic larval stage. Adults are medium-sized flower flies commonly found on flowers, where they feed on nectar and pollen. The species has a disjunct distribution, occurring from Mexico northward along coastal areas of the United States, with additional records from South America. The larvae are aquatic rat-tailed maggots that inhabit organic-rich standing water.
Palpada pusilla
Bicolored Plushback
Palpada pusilla is a species of syrphid fly in the family Syrphidae, commonly known as the Bicolored Plushback. It is a member of the tribe Eristalini, which includes species whose larvae are known as "rat-tailed maggots" due to their distinctive posterior breathing siphon. The species has been documented across all 27 states of Brazil based on distribution records. Adult flies are pollinators that visit flowers, while larvae develop in organic-rich aquatic environments.
Palpada texana
Wide-eyed Plushback
Palpada texana is a species of hoverfly (family Syrphidae) in the tribe Eristalini. Like other members of its genus, it is associated with aquatic or semi-aquatic larval habitats typical of the Eristalina subtribe. The species was described by Hull in 1925. Adults are presumably pollinators, though specific behavioral observations for this species are limited.
Palpada undescribed-species-near-furcata
An undescribed species in the hoverfly genus Palpada, closely related to P. furcata. As a member of tribe Eristalini, its larvae are rat-tailed maggots—aquatic larvae with an extensible posterior breathing siphon that allows respiration while living in oxygen-poor, organic-rich waters. The genus Palpada includes species commonly found in urban, suburban, and rural areas in putrid standing water.
Parapoynx obscuralis
obscure pondweed moth, American china-mark, vallisneria leafcutter
Parapoynx obscuralis is an aquatic moth in the family Crambidae, first described by Augustus Radcliffe Grote in 1881. The species is native to North America, with a range extending from Nova Scotia to Florida and west to Texas, Wisconsin, and Ontario. It has been introduced to Great Britain, where it is naturalised in aquatic nurseries. The larvae are aquatic and feed on submerged aquatic plants.
Parhelophilus porcus
black bog fly
Parhelophilus porcus, commonly known as the black bog fly, is an uncommon syrphid fly species recorded from northern North America. Adults are flower-visiting insects that obtain nectar and pollen from blooms. The species possesses the rat-tailed larval form characteristic of related aquatic or semi-aquatic hoverflies, with an elongated breathing siphon.
Petrophila schaefferalis
Schaeffer's Petrophila
Petrophila schaefferalis is a small crambid moth described by Harrison Gray Dyar Jr. in 1906. The species exhibits sexual dimorphism in size, with females notably larger than males. Adults are active from spring through early autumn. The larvae are aquatic, a characteristic shared with other members of the genus Petrophila. The species occurs in the southwestern United States and Mexico.
Polydontomyia curvipes
Dimorphic Sickleleg
Polydontomyia curvipes, commonly known as the dimorphic sickleleg, is a species of hoverfly (family Syrphidae) and the sole member of its monotypic genus. Formerly classified under Lejops, it was reassigned to the resurrected genus Polydontomyia based on morphological and phylogenetic evidence. The species exhibits sexual dimorphism in leg structure, with males possessing the distinctive curved hind legs referenced in its specific epithet. As a member of the Eristalini tribe, it is associated with aquatic or semi-aquatic larval habitats typical of rat-tail maggot flies.
Prionocyphon
marsh beetles
Prionocyphon is a genus of marsh beetles in the family Scirtidae, containing at least 20 described species. The genus has a broad distribution spanning the Northern Hemisphere and Australia. Species are associated with moist microhabitats, particularly water-filled tree holes and similar lentic environments. The Australian species P. niger was described from rainforest and wet sclerophyll forest habitats in Queensland and New South Wales.
Psellidotus
Psellidotus is a genus of soldier flies in the family Stratiomyidae, subfamily Stratiomyinae, and tribe Stratiomyini. The genus was established by Rondani in 1863 and contains approximately 50 described species distributed primarily in the New World, with greatest diversity in the Neotropical region. Adults are characterized by patterned eyes with horizontal banding, a trait associated with detection of horizontally polarized light and linked to the aquatic larval habitat typical of stratiomyine flies. The genus is taxonomically challenging, particularly in South America where species boundaries with the related genus Hedriodiscus become unclear.
Psellidotus annamariae
soldier fly
Psellidotus annamariae is a species of soldier fly in the family Stratiomyidae, first described by Brimley in 1925. It belongs to the subfamily Stratiomyinae and tribe Stratiomyini. The genus Psellidotus is closely related to Odontomyia and Hedriodiscus, with species boundaries becoming less distinct in the Neotropics. Like other stratiomyine soldier flies, adults typically exhibit strikingly patterned eyes with horizontal banding, a trait associated with detection of horizontally polarized light and linked to aquatic larval habitats.
Psellidotus defectus
Psellidotus defectus is a species of soldier fly in the family Stratiomyidae, subfamily Stratiomyinae. The genus Psellidotus belongs to the tribe Stratiomyini and is closely related to Hedriodiscus, with which it can be difficult to distinguish in the Neotropics. Like other members of the subfamily Stratiomyinae, the larvae are aquatic. Adults are known to visit flowers, and species in this genus exhibit strikingly patterned eyes with horizontal banding, an adaptation associated with detection of horizontally polarized light that may aid in locating aquatic habitats for oviposition.
Psellidotus hieroglyphicus
soldier fly
Psellidotus hieroglyphicus is a species of soldier fly in the family Stratiomyidae. It is one of numerous species in the genus Psellidotus, which belongs to the subfamily Stratiomyinae. The species was described by Olivier in 1811. Like other members of its subfamily, the larvae are aquatic. Adults are characterized by patterned eyes with horizontal banding, a trait shared with many stratiomyine flies and thought to be associated with detection of horizontally polarized light for locating water sources.
Psellidotus novella
Psellidotus novella is a soldier fly species in the family Stratiomyidae, subfamily Stratiomyinae. The genus Psellidotus belongs to the tribe Stratiomyini, a group characterized by aquatic larvae and adults that often exhibit striking eye patterns. Species in this genus are poorly known in the Neotropics, with most known only from original descriptions. The specific epithet "novella" suggests a relatively recent description, though detailed published information on this particular species remains limited.
Pseudolimnophila contempta
Pseudolimnophila contempta is a species of crane fly in the family Limoniidae, described by Osten Sacken in 1869. It belongs to a genus characterized by reduced wing venation and aquatic or semi-aquatic larval habitats. The species occurs across eastern North America, from Ontario and Newfoundland south to Kansas and Florida. Like other limoniid crane flies, adults are delicate, long-legged flies with slender bodies. The genus name refers to its superficial resemblance to true limoniids of the genus Limnophila.
Psorophora signipennis
Mottled Mosquito
Psorophora signipennis, commonly known as the Mottled Mosquito, is a species of mosquito in the family Culicidae. The species is distributed across Middle America and North America. Like other members of the genus Psorophora, it is presumed to be a predatory mosquito with larvae that feed on other mosquito larvae, though specific behavioral studies for this species have not been documented. Adult females are blood-feeders, while both sexes consume nectar for flight energy.
Psychodidae
Moth flies, Drain flies, Sink flies, Filter flies, Sewer gnats, Sand flies
Psychodidae is a large family of true flies comprising over 2,600 described species worldwide, with highest diversity in humid tropical regions. Members exhibit distinctive short, hairy bodies and wings that create a moth-like appearance. The family encompasses two ecologically divergent groups: non-biting moth flies that inhabit moist, decaying organic matter and plumbing systems, and blood-feeding sand flies (subfamily Phlebotominae) that serve as disease vectors.
Psychodomorpha
Psychodomorpha is a nematoceran infraorder of flies comprising three families—Psychodidae, Blephariceridae, and Tanyderidae—plus the superfamily Scatopsoidea (Canthyloscelidae, Scatopsidae, Valeseguyidae). These flies are generally small to minute with hairy or scaled wings and long, often multi-segmented antennae. The group includes moth flies, sand flies, and other obscure dipterans with diverse aquatic and semi-aquatic larval habitats.
Ptychoptera quadrifasciata
phantom crane fly
Ptychoptera quadrifasciata is a species of phantom crane fly in the family Ptychopteridae. The common name 'phantom crane fly' refers to the family's characteristic hovering behavior and delicate appearance. Adults are typically found in moist, wooded habitats near streams or wetlands. Larvae develop in aquatic or semi-aquatic environments with decaying organic matter. The species is native to eastern North America.
Sericomyia bifasciata
Long-nosed Pond Fly
Sericomyia bifasciata, commonly known as the Long-nosed Pond Fly, is an uncommon species of syrphid fly described by Williston in 1887. It belongs to the genus Sericomyia, whose larvae are known as "rat-tailed maggots" with long breathing siphons adapted to aquatic environments. However, the larvae of this particular species remain unknown. Adults have been observed in the northeastern part of North America.
Sericomyia chalcopyga
Sericomyia chalcopyga is a species of syrphid fly (hoverfly) in the family Syrphidae. As a member of the tribe Sericomyiini, its larvae are "rat-tailed maggots" with extensible posterior breathing siphons adapted to aquatic environments. The species was described by Loew in 1863. Like other Sericomyia species, adults are pollinators that visit flowers for nectar and pollen.
Sericomyia lata
White-spotted Pond Fly
Sericomyia lata is a syrphid fly commonly known as the White-spotted Pond Fly. Adults are medium-sized hoverflies, 11.6–15.2 mm in length, with distinctive black bodies and large white abdominal spots. The species is widespread across North America, with highest concentrations in eastern regions. Like other members of its genus, the larvae develop in aquatic or semi-aquatic habitats and possess the characteristic rat-tailed breathing siphon typical of Sericomyia.
Sericomyia nigra
Polar Pond Fly
Sericomyia nigra is a species of hoverfly (family Syrphidae) described by Portschinsky in 1873. It belongs to the tribe Milesiini within subfamily Eristalinae. The species is known from Scandinavia (Norway and Sweden) based on distribution records. As a member of the genus Sericomyia, its larvae likely develop in bog mat pools, though this specific habitat association has not been directly documented for S. nigra itself. Adults are presumably pollinators, as is characteristic of the family.
Sericomyia sexfasciata
Six-banded Pond Fly
Sericomyia sexfasciata is a species of syrphid fly (family Syrphidae) commonly known as the Six-banded Pond Fly. It belongs to the subfamily Eristalinae and tribe Milesiini. Like other members of its genus, the larvae develop in aquatic or semi-aquatic habitats. The species was first described by Francis Walker in 1849.
Sericomyia tolli
Great-nosed Pond Fly
Sericomyia tolli is a species of hoverfly (family Syrphidae) described by Frey in 1915. It belongs to the genus Sericomyia, whose larvae are known as 'rat-tailed maggots' and inhabit aquatic environments. The species is poorly documented in scientific literature, with minimal observational records available.
Sialis
Holarctic Alderflies
Sialis is a genus of alderflies in the family Sialidae, characterized by small, brown, heavy-bodied insects with forewings 10–20 mm long. The genus is distinguished from other Megaloptera by having fewer than fifteen square cells along the upper edge of the front wings. Adults are diurnal and active in late spring. Larvae are aquatic predators that develop over two years before pupating in shoreline soil.
Simuliidae
black flies, buffalo gnats, turkey gnats, white socks
Black flies are small, humpbacked flies in the family Simuliidae, comprising over 2,200 formally described species. Only females bite, using serrated mandibles to slash skin and lap pooled blood for egg development. They are vectors of Leucocytozoon parasites causing leucocytozoonosis in birds and, in some regions, filarial worms causing river blindness in humans. Larvae develop exclusively in flowing freshwater, attaching to submerged substrates with specialized hooks.
Simulium annulus
Ringed Black Fly
Simulium annulus is a species of black fly in the family Simuliidae, first described by Lundstrom in 1911 under the basionym Melusina annula. It belongs to the large genus Simulium, which comprises blood-feeding dipterans commonly known as black flies or buffalo gnats. The common name "Ringed Black Fly" suggests a distinctive annular marking pattern, though specific morphological details are not well documented in available sources. Like other simuliids, it likely has an aquatic larval stage and terrestrial adult stage.
Simulium tuberosum
Twinn's black fly, superfluous black fly, tubercled black fly
Simulium tuberosum is a species of black fly (family Simuliidae) first described by Lundström in 1911. It belongs to the S. tuberosum species group, a cytologically complex assemblage of sibling species distinguished primarily by chromosomal characteristics. The species has been recorded from Norway, Sweden, Alaska, and northeastern North America. Like other black flies, it has aquatic larval and pupal stages and terrestrial adults.
Sisyra nigra
Black Spongillafly, Black Spongefly
Sisyra nigra is a small lacewing in the family Sisyridae, commonly known as the Black Spongillafly. It is the most widely distributed of the three British Sisyridae species and occurs across the Holarctic region. The species has a unique life cycle with fully aquatic larvae that are specialized predators of freshwater sponges, while adults are terrestrial and dispersive. S. nigra is notable for its distinctive achiasmatic sex chromosome segregation mechanism during male meiosis, which differs from other Neuroptera and supports the basal phylogenetic position of Sisyridae within the order.
Sphegina campanulata
Orange-horned Hammertail, Orange-horned Pufftail
Sphegina campanulata is a syrphid fly (hoverfly) species described by Robertson in 1901. It is fairly common in the northeastern United States. The species is known for its distinctive orange-horned appearance and is one of approximately 45 observations documented on iNaturalist. Like other members of the genus Sphegina, it exhibits the characteristic hovering flight ability common to syrphid flies.
Stenomicra
Stenomicra is a genus of small flies in the family Periscelididae, first described by Coquillett in 1900. The genus contains more than 20 described species, with at least one species documented from phytotelmata of Araceae plants in the Neotropical Region. Larval stages have been described for at least one species, indicating development within plant-held water bodies.
Stilobezzia
Stilobezzia is a genus of predaceous biting midges in the family Ceratopogonidae, comprising more than 330 described species worldwide. Adult females are predators of other small insects. Immature stages develop in aquatic and semiaquatic habitats. The genus is absent from Antarctica and some islands.
Stratiomyinae
Stratiomyinae is a subfamily of soldier flies (family Stratiomyidae) containing approximately 40 genera arranged in three tribes: Oxycerini, Prosopochrysini, and Stratiomyini. Members are distinguished by larvae that are aquatic or semi-aquatic, a trait that separates them from many other stratiomyid subfamilies. Adults often exhibit striking eye patterns with horizontal banding, which has been linked to polarization vision potentially used for locating water surfaces for mating and oviposition. The subfamily has a cosmopolitan distribution with significant diversity in both Nearctic and Neotropical regions.
Stratiomyini
soldier flies
Stratiomyini is a tribe of soldier flies (family Stratiomyidae) characterized by adults with strikingly patterned eyes that often display horizontal banding. Members of this tribe are frequently wasp- or bee-mimics in appearance. The tribe includes genera such as Odontomyia, Psellidotus, and Hedriodiscus. Larvae of the subfamily Stratiomyinae, which includes Stratiomyini, are aquatic.
Stratiomyomorpha
Soldier Flies and Allies
Stratiomyomorpha is a parvorder of brachyceran flies comprising approximately 3,000 species, dominated by the family Stratiomyidae (soldier flies) with two smaller associated families. The group is characterized by broad morphological diversity ranging from slender to robust body forms. Larvae occupy varied aquatic and semi-aquatic habitats. Adults are often conspicuous, frequently displaying metallic coloration.
Stratiomys normula
Stratiomys normula is a species of soldier fly in the family Stratiomyidae, first described by Loew in 1866. It is one of several North American species in the genus Stratiomys that exhibit wasp-mimicking coloration. The species has been recorded from Canada and the United States. Like other members of its genus, it is diurnal and associated with wetland habitats where its larvae develop.
Tabanini
horse flies, deer flies
Tabanini is a tribe of horse and deer flies within the family Tabanidae, containing at least 220 described species. Members are robust, medium to large flies with prominent eyes and biting mouthparts. The tribe includes economically significant genera such as Tabanus and Hybomitra, many of which are biting pests of mammals including humans and livestock.
Tabanus
True Horse Flies, Horse Flies
Tabanus is a large genus of biting horse flies in the family Tabanidae, containing hundreds of species distributed worldwide. Females possess scissor-like mouthparts adapted for cutting skin to access blood meals from mammals, including livestock and humans. The genus includes some of the largest horse flies in North America, with species such as Tabanus americanus reaching up to 30 mm in body length. Members of this genus are significant from a veterinary and medical perspective as potential vectors of pathogens including anthrax, worms, and trypanosomes.
Telebasis
Firetails
Telebasis is a genus of damselflies in the family Coenagrionidae, occurring throughout the Neotropics. Most species display red coloration, though a few blue species occur in South America. The genus was taxonomically revised by Rosser Garrison in 2009. Larval morphology varies among species; for example, Telebasis obsoleta has five palpal setae, a trait shared only with T. demerara, while other species have six or seven.
Tipulidae
Large Crane Flies, Crane Flies
Tipulidae is a large family of true flies in the order Diptera, comprising over 4,200 described species in more than 30 genera. Members are commonly known as crane flies or large crane flies, characterized by their elongated bodies and exceptionally long, slender legs. Adults are typically short-lived and often do not feed; their primary purpose is reproduction. Larvae occupy diverse moist habitats including soil, leaf litter, decaying wood, and aquatic environments, where most feed on decaying organic matter. The family has a fossil record extending to the Late Jurassic.
DipteraNematoceracrane-fliesdecomposerssaprophagousshort-lived-adultsmating-swarmsturfgrass-pestsharmless-to-humansworldwide-distributionLate-Jurassic-fossilsCharles-Paul-Alexandermaxillary-palps13-antennal-segmentsLimoniidaePediciidaemosquito-hawk-misnomerdaddy-longlegs-confusionleatherjacketsaquatic-larvaeterrestrial-larvaespring-emergencelight-attractionwingless-snow-crane-flies-in-genus-Chionea-(now-Limoniidae)Tropidia quadrata
Common Thick-leg Fly, Common Thickleg Fly
Tropidia quadrata is a species of hoverfly (Syrphidae) found across north-central North America. Adults are commonly observed on flowers, where they feed on nectar and pollen. The larvae are aquatic, a distinctive trait within the family. The species is notable for its thickened hind legs, which give rise to its common name.