Aquatic-insect
Guides
Skwala americana
American springfly
Skwala americana, commonly known as the American springfly, is a species of stonefly in the family Perlodidae. It is distributed across western North America, with records from Alberta, Arizona, British Columbia, California, Colorado, and other regions. As a member of the order Plecoptera, it has an aquatic larval stage and terrestrial adult stage, typical of stoneflies.
Smicridea dispar
Smicridea dispar is a species of netspinning caddisfly in the family Hydropsychidae, originally described by Banks in 1905 as Polycentropus dispar. It belongs to the order Trichoptera, an aquatic insect order whose larvae are commonly known as caddisflies. The species is documented from North America. As a member of Hydropsychidae, its larvae likely construct fixed retreats with capture nets in flowing water, though specific behavioral details for this species remain limited.
Smicridea signata
netspinning caddisfly
Smicridea signata is a species of netspinning caddisfly in the family Hydropsychidae. The species is found in North America and belongs to the Smicridea (Smicridea) fasciatella species group, which is characterized by a phallic apparatus that is a simple tube with eversible internal sclerites at the apex. The fasciatella group has a broad distribution from the southwestern USA through Central America, the Greater Antilles, and most of South America.
Soyedina nevadensis
Nevada Forestfly
Soyedina nevadensis is a species of stonefly in the family Nemouridae, commonly known as the Nevada Forestfly. It was described by Claassen in 1923. The species belongs to the order Plecoptera, a group of aquatic insects whose nymphs typically inhabit cold, clean streams.
Soyedina washingtoni
vernal forestfly
Soyedina washingtoni, commonly known as the vernal forestfly, is a species of spring stonefly in the family Nemouridae. It was first described by Claassen in 1923 under the basionym Nemoura washingtoni. As a member of the order Plecoptera, it belongs to a group of aquatic insects whose nymphal stages develop in freshwater habitats.
Spinadis simplex
Wallace's Deepwater Mayfly
Spinadis simplex is a species of mayfly in the family Heptageniidae, commonly known as Wallace's Deepwater Mayfly. It is a North American species first described by Walsh in 1863. The genus Spinadis is distinguished within the Heptageniidae by specific morphological characteristics related to wing venation and genitalia structure. Like other members of the family, S. simplex has aquatic nymphal stages and winged adult stages with brief adult lifespans.
Stegopterna mutata
mutated black fly
Stegopterna mutata is a species of black fly in the family Simuliidae, first described by Malloch in 1914 under the basionym Prosimulium mutatum. The species belongs to the tribe Prosimuliini, a group of primitive black flies. Like other simuliids, adults are small, blood-feeding dipterans with aquatic larval stages. The specific epithet "mutata" (Latin for "changed" or "mutated") gives rise to its common name "mutated black fly."
Stenacron carolina
Carolina flat-headed mayfly
Stenacron carolina is a species of flatheaded mayfly in the family Heptageniidae. It is found in North America. The species was described by Banks in 1914. Like other members of the genus Stenacron, it is associated with aquatic habitats.
Stenacron minnetonka
flatheaded mayfly
Stenacron minnetonka is a species of flatheaded mayfly in the family Heptageniidae, first described by Daggy in 1945. It is known from North America. The species belongs to a genus of aquatic insects whose larvae inhabit flowing freshwater environments. Limited observational data are available for this species specifically.
Stenacron pallidum
flatheaded mayfly
Stenacron pallidum is a species of flatheaded mayfly in the family Heptageniidae. It is found in the eastern United States. Like other members of the genus Stenacron, it is associated with freshwater stream habitats.
Stenelmis cheryl
Cheryl's Riffle Beetle
Stenelmis cheryl, commonly known as Cheryl's riffle beetle, is a species of riffle beetle in the family Elmidae. The species was described by Brown in 1987. Riffle beetles are aquatic insects typically associated with flowing water habitats. Stenelmis cheryl has been documented in Central America and North America based on occurrence records.
Stenelmis crenata
riffle beetle
Stenelmis crenata is a species of riffle beetle in the family Elmidae, occurring in North America. It inhabits fast-flowing stream environments, particularly riffle habitats in tallgrass prairie streams. The species exhibits a multivoltine life cycle with overlapping cohorts and year-round larval presence. Adults are active from late spring through autumn.
Stenelmis decorata
Stenelmis decorata is a species of riffle beetle in the family Elmidae, described by Sanderson in 1938. Riffle beetles are aquatic insects associated with flowing water habitats. The species is known to occur in North America.
Stenelmis occidentalis
Neararctic Riffle Beetle
Stenelmis occidentalis is a species of riffle beetle in the family Elmidae, described by Schmude and Brown in 1991. Riffle beetles are aquatic insects adapted to life in fast-flowing freshwater habitats. The species is found in both Central America and North America, reflecting a transcontinental distribution across the Nearctic region.
Stenelmis sexlineata
riffle beetle
Stenelmis sexlineata is a riffle beetle in the family Elmidae, described by Sanderson in 1938. It inhabits flowing water environments in North America and has a multi-year life cycle with distinct larval stages. Like other elmid beetles, it is adapted to life in fast-moving streams and rivers.
Stenochironomus albipalpus
Stenochironomus albipalpus is a species of non-biting midge (Chironomidae) described by Borkent in 1984. The species belongs to the subfamily Chironominae and tribe Chironomini. It is currently recognized as a valid species in GBIF and iNaturalist databases, though Catalogue of Life lists it as a synonym. Records indicate limited observational data with only 10 observations documented on iNaturalist.
Stenochironomus colei
Stenochironomus colei is a species of non-biting midge in the family Chironomidae, described by Malloch in 1919. The genus Stenochironomus comprises small to medium-sized chironomid midges. As with many members of this large family, specific ecological and biological details for this particular species remain poorly documented in available literature.
Stenochironomus hilaris
Stenochironomus hilaris is a non-biting midge in the family Chironomidae, originally described by Walker in 1848. The species has been recognized under three junior synonyms (S. taeniapennis, S. zonopterus, and S. exquisitus) that were synonymized based on revisionary work on the Stenochironomus complex. As a member of the subgenus Stenochironomus s.str., its larvae are specialized wood miners with highly modified morphology including dorsoventrally flattened head capsules, expanded thoracic segments, and long, flaccid abdomens. The species occurs in the Nearctic and Neotropical regions.
Stenochironomus poecilopterus
Stenochironomus poecilopterus is a species of non-biting midge in the family Chironomidae, originally described by Mitchell in 1908. As a member of the genus Stenochironomus, it belongs to a group of chironomid midges characterized by reduced wing venation and specific larval adaptations. The species is recognized as valid and accepted in current taxonomic databases.
Stenochironomus pulchripennis
Stenochironomus pulchripennis is a species of non-biting midge in the family Chironomidae, first described by Coquillett in 1902. The genus Stenochironomus is characterized by reduced wing venation and includes species often associated with decaying wood and aquatic habitats. Like other chironomids, adults do not feed and rely on larval energy reserves.
Stenochironomus woodi
Stenochironomus woodi is a species of non-biting midge in the family Chironomidae, described by Borkent in 1984. It belongs to the genus Stenochironomus, a group of chironomid midges characterized by reduced mouthparts and often associated with aquatic or semi-aquatic habitats. The species is known from limited records, with 11 observations documented on iNaturalist.
Stenonema
Stenonema is a genus of mayflies in the family Heptageniidae. Species within this genus are aquatic insects found in freshwater environments, with nymphs inhabiting both riffle and pool habitats. The genus has been extensively studied in ecological and toxicological research, particularly regarding morphological variation, behavioral responses to environmental cues, and sensitivity to pollutants. Multiple species, including S. modestum, S. tripunctatum, and S. vicarium, serve as bioindicators for water quality assessment.
Stenopelmus
marsh weevils
Stenopelmus is a genus of marsh weevils comprising at least two described species. The genus is best known for Stenopelmus rufinasus, a North American weevil introduced to Europe in the late 19th century alongside its host plant Azolla filiculoides. Members of this genus are specialized herbivores associated with aquatic ferns and have been employed as biological control agents for invasive water fern management.
Stenopelmus rufinasus
Azolla Weevil, Waterfern Weevil
Stenopelmus rufinasus is a small weevil native to North America, introduced to Europe in 1898 alongside its host plant Azolla filiculoides. The species is a specialized herbivore with rapid development, completing its life cycle in approximately 20 days and producing 4-6 generations annually under favorable conditions. It has been widely deployed as a biological control agent for invasive Azolla species, particularly in South Africa where it has achieved dramatic population reductions. Adults exhibit exceptional dispersal capabilities, documented to travel up to 350 km, and frequently occur in water bodies lacking visible host plants.
Stilobezzia sybleae
Stilobezzia sybleae is a species of predaceous biting midge in the family Ceratopogonidae, described by Wirth in 1953. The genus Stilobezzia comprises small, predatory midges whose larvae and adults feed on other small invertebrates. The species epithet honors Syble, likely referring to a person significant to the describer.
Susulus venustus
Susulus venustus is a stonefly species in the family Perlodidae, described by Jewett in 1965. It belongs to the genus Susulus within the tribe Perlodini. The species is known from California in western North America. As a member of the Plecoptera order, it is part of the aquatic insect community associated with freshwater habitats.
Suwallia
green stoneflies
Suwallia is a genus of green stoneflies (Plecoptera: Chloroperlidae) in the tribe Suwalliini, comprising more than 20 described species. The genus is distributed across the East Palearctic and Nearctic regions, including Russia, Mongolia, Japan, North America, and China. Adult males possess distinctive genitalic structures used for species identification, such as specialized sclerites on tergum X. The genus was established by Ricker in 1943.
Sweltsa borealis
Boreal Sallfly
Sweltsa borealis, known as the boreal sallfly, is a species of green stonefly in the family Chloroperlidae. It is native to North America with documented records from Alaska, Alberta, British Columbia, California, and Colorado. As a member of the Chloroperlidae family, it belongs to a group commonly referred to as green stoneflies or sallflies. The species was first described by Banks in 1895.
Sweltsa coloradensis
Colorado Sallfly
Sweltsa coloradensis, known as the Colorado sallfly, is a green stonefly species in the family Chloroperlidae. It is found in western North America, with records from Alaska, Alberta, British Columbia, California, and Arizona. Like other members of its family, it likely inhabits cold, clean streams. The species was described by Nathan Banks in 1898.
Sweltsa naica
Northeastern Sallfly
Sweltsa naica, commonly known as the northeastern sallfly, is a species of green stonefly in the family Chloroperlidae. It is known from a restricted distribution in northeastern North America. The species was described by Provancher in 1876. As a member of Chloroperlidae, it belongs to a family commonly referred to as green stoneflies or sallflies.
Sweltsa onkos
Ontario Sallfly
Sweltsa onkos, commonly known as the Ontario sallfly, is a species of green stonefly in the family Chloroperlidae. It belongs to the order Plecoptera, an ancient group of aquatic insects. The species has been documented in northeastern North America.
Taenionema
winter stoneflies
Taenionema is a genus of winter stoneflies (Plecoptera: Taeniopterygidae) comprising approximately 14 described species. The genus was established by Banks in 1905 with Taenionema analis as the type species. Species are distributed across the Nearctic and eastern Palearctic regions, with 13 species native to North America and one species (T. japonicum) ranging across Japan, Korea, Mongolia, Russia and northeastern China. A second Eastern Hemisphere species, T. sinensis, was described in 2023 from southeastern China.
Taenionema californicum
California willowfly
Taenionema californicum, commonly known as the California willowfly, is a species of winter stonefly in the family Taeniopterygidae. It is native to North America, with documented presence in California. As a member of the order Plecoptera, it is associated with freshwater habitats. The species was first described by Needham and Claassen in 1925.
Taenionema oregonense
Oregon Willowfly
Taenionema oregonense, commonly known as the Oregon Willowfly, is a species of winter stonefly in the family Taeniopterygidae. The species was described by Needham & Claassen in 1925. It belongs to the order Plecoptera, a group of aquatic insects whose nymphs develop in freshwater habitats.
Taeniopteryx nivalis
boreal willowfly
Taeniopteryx nivalis, commonly known as the boreal willowfly, is a winter stonefly species in the family Taeniopterygidae. It is native to North America and has been recorded from multiple regions including Alberta, California, Connecticut, Delaware, and Idaho. As a member of the order Plecoptera, it belongs to a group of aquatic insects whose nymphs develop in freshwater habitats. The species was first described by Fitch in 1847.
Tallaperla maria
common roachfly
Tallaperla maria, commonly known as the common roachfly, is a stonefly species in the family Peltoperlidae. It is found in North America, with records from Alabama, Connecticut, Delaware, Georgia, and Kentucky. The species has been studied at the Fernow Experimental Forest in West Virginia, where research examined its abundance, life history, and production alongside the related Peltoperla arcuata.
Tanypus
non-biting midges
Tanypus is a genus of non-biting midges in the family Chironomidae, subfamily Tanypodinae, comprising at least 100 described species. Larvae are aquatic and benthic, occurring in freshwater lakes and other lentic environments. Species within the genus exhibit bioturbation activity that modifies sediment oxygen dynamics. Life cycle patterns vary by species, with some showing multivoltine generations and specific overwintering strategies.
Tanypus neopunctipennis
Tanypus neopunctipennis is a species of non-biting midge in the family Chironomidae, described by Sublette in 1964. It belongs to the subfamily Tanypodinae, a group of predatory or scavenging midges. The species is accepted in modern taxonomic databases, though some sources list it as a synonym. Available records indicate limited published information on its biology and ecology.
Tanypus punctipennis
Tanypus punctipennis is a non-biting midge species in the family Chironomidae, subfamily Tanypodinae. It has been documented in European freshwater habitats, particularly Lake Balaton in Hungary, where research indicates a trivoltine life cycle with overlapping generations and extended emergence periods. The species is part of the diverse Tanypus genus, which are predatory midges found in aquatic environments.
Teloganopsis
spiny crawler mayfly
Teloganopsis is a genus of spiny crawler mayflies (Ephemeroptera: Ephemerellidae) comprising approximately 17 described species. The genus was established by Ulmer in 1939 and occurs primarily in the Oriental region. Recent taxonomic work in Thailand has used integrative approaches combining morphology and molecular data (COI and 28S rDNA) to distinguish species, with abdominal color patterns serving as consistent diagnostic characters across developmental stages. Species in this genus have been documented from Thailand and other parts of Asia, though many remain poorly known due to limited collection and study.
Teloganopsis deficiens
little black quill
Teloganopsis deficiens, commonly known as the little black quill, is a species of spiny crawler mayfly in the family Ephemerellidae. It was first described by Morgan in 1911. The species occurs in North America and is part of a mayfly group characterized by crawling behavior and spiny body features. Like other Ephemerellidae, it has an aquatic larval stage and short-lived adult form.
Thraulodes speciosus
Thraulodes speciosus is a species of mayfly in the family Leptophlebiidae, described by Traver in 1934. It belongs to the order Ephemeroptera, an ancient group of aquatic insects with brief adult stages. The genus Thraulodes is distributed across the Nearctic and Neotropical regions. Like other leptophlebiid mayflies, this species has aquatic nymphal stages and terrestrial adults that do not feed.
Timpanoga hecuba
Great Red Quill
Timpanoga hecuba, commonly known as the Great Red Quill, is a species of mayfly in the family Ephemerellidae. This Nearctic species is significant in fly fishing, where its adult and subimago (dun) forms are imitated by artificial flies. The species was originally described as Ephemerella hecuba by Eaton in 1884 and later transferred to the genus Timpanoga.
Tinodes
Tinodes is a genus of caddisflies in the family Psychomyiidae, first described by John Curtis in 1834. The genus has a cosmopolitan distribution with the richest species assemblages in the Oriental region and southern Western Palearctic. Species have been documented from Europe, Africa, Madagascar, the Comoros, and Asia. Larvae of at least some species construct fixed tunnel-like retreats (galleries) on stone surfaces in freshwater streams. The genus serves as an important bioindicator of freshwater ecosystem health due to its sensitivity to environmental changes.
Tortopsis primus
Manitoba white burrowing mayfly
Tortopsis primus is a species of burrowing mayfly in the family Polymitarcyidae, described by McDunnough in 1924. It is commonly known as the Manitoba white burrowing mayfly. The species belongs to the order Ephemeroptera, an ancient group of aquatic insects with aquatic immature stages and short-lived winged adults. As a member of Polymitarcyidae, it exhibits the family characteristic of burrowing habits in its nymphal stage.
Tortopsis puella
Tortopsis puella is a species of burrowing mayfly in the family Polymitarcyidae, originally described by Pictet in 1843. It belongs to a genus characterized by fossorial (burrowing) larvae that inhabit sandy or muddy substrates in freshwater environments. The species is known from the Nearctic region, with records from North America.
Trepobates taylori
Trepobates taylori is a water strider species in the family Gerridae, characterized by its broad Neotropical distribution spanning from southern Texas through Mexico, Central America, the Caribbean, and South America to northern Argentina. The species was described by Kirkaldy in 1899 and belongs to the subfamily Trepobatinae, a group of gerrids adapted to life on the water surface.
Triacanthagyna caribbea
Caribbean Darner
Triacanthagyna caribbea is a species of darner dragonfly in the family Aeshnidae, described by Williamson in 1923. It is endemic to the Caribbean region, with confirmed records from Colombia (departments of Antioquia, Bolívar, Magdalena, and Sucre) and broader Caribbean distribution. The species is part of the genus Triacanthagyna, which is characterized by three-spined abdominal appendages in males. As with other aeshnids, it is likely a strong flier adapted to tropical environments.
Triaenodes
Triaenodes is a genus of long-horned caddisflies (family Leptoceridae) containing at least 170 described species. The genus has a cosmopolitan distribution, with species documented across the Neotropics, North America, Europe, and Asia. Larvae construct portable cases and are primarily aquatic, with some species exhibiting specialized swimming behavior to navigate between aquatic macrophytes. The genus serves as the type genus for the tribe Triaenodini.
Triaenodes aba
Aba's Long-horned Caddisfly
Triaenodes aba is a species of long-horned caddisfly in the family Leptoceridae, described by Milne in 1935. The common name references its notably elongated antennae, which extend well beyond the body length—a characteristic trait of the genus. As with other Leptoceridae, the larvae are aquatic and construct portable cases from plant material or sand grains. Adult emergence patterns and specific habitat preferences for this species remain poorly documented, with only four verified observations recorded on iNaturalist.