Aquatic-insect
Guides
Optioservus browni
Brown's optioservus riffle beetle
Optioservus browni is a species of riffle beetle (family Elmidae) described by White in 1978. The species is known from North America and is part of a genus of aquatic beetles typically found in flowing water habitats. Like other elmid beetles, it is adapted to life in fast-moving streams and rivers.
Optioservus immunis
Optioservus immunis is a species of riffle beetle in the family Elmidae, first described by Fall in 1925. It is one of thirteen Nearctic species in the genus, distinguished from congeners primarily by male genitalia and elytral pattern. The species was previously known under the synonym Optioservus cryophilus.
Optioservus ovalis
Optioservus ovalis is a species of riffle beetle in the family Elmidae, first described by LeConte in 1863. Riffle beetles are aquatic insects whose larvae and adults inhabit running water environments. The species is found in North America, with records from Canada and the United States. Like other elmid beetles, it is likely associated with clean, well-oxygenated streams and rivers.
Oreodytes alaskanus
Oreodytes alaskanus is a small predaceous diving beetle in the family Dytiscidae, first described by Fall in 1926. It belongs to the subfamily Hydroporinae, one of the most diverse lineages of diving beetles. The species is associated with freshwater habitats in northern North America.
Orohermes crepusculus
Orohermes crepusculus is a species of fishfly in the family Corydalidae, originally described as Dysmicohermes crepusculus by Chandler in 1954. It is one of several species in the genus Orohermes, which comprises small to medium-sized megalopterans found in western North America. The species epithet "crepusculus" refers to twilight, possibly alluding to crepuscular activity patterns. Adults are weak fliers and are often attracted to lights.
Oroperla barbara
Gilltail Springfly
Oroperla barbara is a stonefly species in the family Perlodidae, first described by Needham in 1933. It is commonly known as the Gilltail Springfly. The species is recorded from California and Nevada in western North America. As a member of the order Plecoptera, it belongs to an ancient group of aquatic insects with gilled immature stages and terrestrial adults.
Orthocladius
Orthocladius is a genus of non-biting midges in the family Chironomidae. Larvae are aquatic and construct silk tubes that serve as microhabitats for associated microbial communities. The genus includes species adapted to diverse freshwater environments, including streams and hygropetric habitats.
Osobenus
Osobenus is a genus of stoneflies in the family Perlodidae, first described by Ricker in 1952. The genus belongs to the tribe Diploperlini within the subfamily Perlodinae. Species in this genus are found in western North America, with records from British Columbia, Washington, Oregon, and California.
Osobenus yakimae
Yakima Springfly
Osobenus yakimae is a species of stonefly in the family Perlodidae, commonly known as the Yakima Springfly. It is distributed across the Pacific Northwest of North America, with records from British Columbia, Washington, Oregon, and California. As a member of the order Plecoptera, it is an aquatic insect with nymphal stages developing in freshwater habitats. The species was first described by Hoppe in 1938.
Ostrocerca albidipennis
white-tailed forestfly, whitetailed forestfly
Ostrocerca albidipennis, commonly called the white-tailed forestfly, is a species of spring stonefly in the family Nemouridae. It was originally described as Nemoura albidipennis by Walker in 1852. The species is found in eastern North America, with records from Connecticut, Maine, Massachusetts, Michigan, and Maryland. As a member of the Nemouridae family, it belongs to the group of small stoneflies commonly known as forestflies.
Ostrocerca complexa
Notched Forestfly
Ostrocerca complexa, commonly known as the notched forestfly, is a species of spring stonefly in the family Nemouridae. First described by Claassen in 1937 as Nemoura complexa, it is now placed in the genus Ostrocerca. It occurs in eastern North America, with documented records from Connecticut, Maine, Massachusetts, New Brunswick, and Nova Scotia.
Ostrocerca dimicki
Hooked Forestfly
Ostrocerca dimicki, commonly known as the hooked forestfly, is a species of spring stonefly in the family Nemouridae. It belongs to the order Plecoptera, a group of aquatic insects whose nymphs inhabit cold, clean streams. The species was described by Frison in 1936. It is recorded from the Pacific Northwest region of North America.
Ostrocerca truncata
Truncate Forestfly
Ostrocerca truncata, commonly known as the truncate forestfly, is a species of spring stonefly in the family Nemouridae. Originally described as Nemoura truncata by Claassen in 1923, it is one of approximately 50 species in the genus Ostrocerca. The species is found in eastern North America, with records from Connecticut, Indiana, Kentucky, Maine, Massachusetts, and other states. Like other Nemouridae, it is associated with cool, clean streams and emerges in spring.
Oxyethira pallida
Oxyethira pallida is a species of microcaddisfly in the family Hydroptilidae, first described by Banks in 1904. It inhabits lentic and slow lotic freshwater systems across North America. As a microcaddisfly, it belongs to a group characterized by reduced larval cases and small adult size compared to other caddisflies.
Oxyethira zeronia
microcaddisfly
Oxyethira zeronia is a species of microcaddisfly described by Ross in 1941. It belongs to the family Hydroptilidae, the largest family of caddisflies, whose members are characterized by their small size and reduced wing venation. The species is recorded from North America, though specific habitat and ecological details remain poorly documented.
Palmacorixa buenoi
Palmacorixa buenoi is a species of water boatman (family Corixidae) described by Abbott in 1913. It is an aquatic heteropteran known for producing acoustic signals, with diel periodicity patterns that differ substantially from those observed in related genera. Most aquatic heteropterans show increased acoustic activity in early evening, but P. buenoi exhibits atypical patterns in song type periodicity. The species occurs in North America, particularly in the Nearctic region excluding the Western Cordillera and Beringia.
Palmacorixa gillettei
Palmacorixa gillettei is a species of water boatman (family Corixidae) in the infraorder Nepomorpha. It was described by Abbott in 1912. The genus Palmacorixa is a small group within the Corixidae, and this species appears to be rarely recorded based on limited observation data. Members of this family are aquatic true bugs found in freshwater habitats.
Pannota
Pannota is an infraorder of mayflies (Ephemeroptera) distinguished from its sister group Schistonota by the degree of wing pad fusion in final-stage nymphs: in Pannota, fusion along the mesothorax is less than half the fore-wing length, whereas in Schistonota it exceeds half. Nymphs are slow-moving crawlers with modified gill morphology, contrasting with the active swimmers, burrowers, and sprawlers of Schistonota. The group includes two superfamilies, Caenoidea and Ephemerelloidea, encompassing seven families. Members are important bioindicators of freshwater ecosystem health due to their sensitivity to pollution.
Paracapnia angulata
angulate snowfly
Paracapnia angulata is a small winter stonefly in the family Capniidae. The species occurs in headwater streams across eastern North America, with documented populations in Appalachian streams affected by acid precipitation. Research indicates it tolerates a wide pH range (4.5–7.5) and can achieve high secondary production in acidic conditions due to increased abundance and biomass, despite lower individual growth rates. Nymphs serve as prey for steelhead trout.
Parachironomus
Parachironomus is a genus of non-biting midges in the family Chironomidae, subfamily Chironominae. The genus has a cosmopolitan distribution with approximately 85 valid species worldwide. Some species are free-living aquatic larvae, while others are endoparasites of freshwater snails. Species have been recorded from diverse habitats including standing and flowing waters, soft sediments, aquatic macrophytes, and artificial urban waterbodies.
Paracloeodes minutus
small minnow mayfly
Paracloeodes minutus is a small minnow mayfly in the family Baetidae. It is found in Central America and North America, including southeastern Canada, northern Mexico, and the continental United States. The species was described by Daggy in 1945.
Paragnetina media
embossed stonefly, Embossed Stone
Paragnetina media, commonly known as the embossed stonefly, is a predaceous stonefly species in the family Perlidae. It is found in North America, with documented populations in Arkansas, Connecticut, Delaware, Illinois, and Indiana. The species has been studied for its sensory morphology, particularly the distribution of sensilla on mouthparts and antennae, and its ecological responses to habitat variables including current speed and substrate composition.
Paraleptophlebia bicornuta
pronggilled mayfly
Paraleptophlebia bicornuta is a species of pronggilled mayfly described by James Halliday McDunnough in 1926. As a member of the family Leptophlebiidae, it possesses the forked gills characteristic of this group. The species is known from North America, with records from the Nearctic region. Like other mayflies, it has an aquatic nymphal stage and a short-lived adult stage.
Paraleptophlebia debilis
mahogany dun
Paraleptophlebia debilis, commonly known as the mahogany dun, is a species of pronggilled mayfly in the family Leptophlebiidae. It was first described by Francis Walker in 1853 under the basionym Baetis debilis. The species is found in North America, though specific details about its ecology and biology remain limited in available sources.
Paraleptophlebia guttata
dappled prong-gilled mayfly
Paraleptophlebia guttata is a prong-gilled mayfly in the family Leptophlebiidae. Adults are known from southeastern Canada, northern Canada, and the eastern United States. The species is part of a diverse genus of stream-dwelling mayflies characterized by forked gills on abdominal segments.
Paraleptophlebia helena
pronggilled mayfly
Paraleptophlebia helena is a species of pronggilled mayfly in the family Leptophlebiidae. The species was described by Day in 1952 and is known to occur in North America. As a member of the Leptophlebiidae, it possesses the characteristic forked gills (pronggills) that give the group its common name.
Paraleptophlebia strigula
streaky prong-gilled mayfly
Paraleptophlebia strigula is a species of prong-gilled mayfly in the family Leptophlebiidae. It was described by McDunnough in 1932. The species occurs in North America. As a member of Leptophlebiidae, it possesses the characteristic forked gills on abdominal segments that give the family its common name.
Paraleuctra sara
Appalachian needlefly
Paraleuctra sara, commonly known as the Appalachian needlefly, is a species of rolled-winged stonefly in the family Leuctridae. It was first described by Claassen in 1937. The species is found in eastern North America, with documented records from Alabama, Connecticut, Delaware, Georgia, and Indiana. As a member of the Leuctridae family, it belongs to a group of stoneflies characterized by their distinctive wing posture at rest.
Paranemoura
Paranemoura is a genus of spring stoneflies in the family Nemouridae, established by Needham & Claassen in 1925. The genus contains at least two described species: P. claasseni (1996) and P. perfecta (1852), the latter commonly known as the spotted forestfly. As members of the order Plecoptera, these insects are aquatic during their immature stages and terrestrial as adults.
Paranemoura perfecta
spotted forestfly
Paranemoura perfecta, commonly known as the spotted forestfly, is a species of spring stonefly in the family Nemouridae. It was first described by Walker in 1852 under the basionym Nemoura perfecta. The species is found in eastern North America, with documented records from Connecticut, Maine, Massachusetts, Michigan, and Maryland. As a member of the Nemouridae, it belongs to the group of spring stoneflies characterized by small size and cold-water habitat associations.
Paraperla
green stoneflies
Paraperla is a genus of green stoneflies in the family Chloroperlidae, established by Banks in 1906. It contains at least two described species: P. frontalis (the hyporheic sallfly) and P. wilsoni. The genus belongs to the subfamily Paraperlinae and is characterized by its association with subterranean or hyporheic aquatic habitats. These stoneflies are part of the Arctoperlaria, a suborder of Plecoptera found primarily in the Northern Hemisphere.
Paraphaenocladius exagitans
Paraphaenocladius exagitans is a non-biting midge in the family Chironomidae. The subspecies P. e. longipes has been recorded from Costa Rica, St. Vincent, Trinidad and Tobago, Guatemala, possibly Bolivia, and more recently from southeastern Brazil. Larvae inhabit small springs with slow water flow and construct delicate tubes using fine-sand grains while mining moss leaves. Development from collection to pupation has been observed to take approximately 20 days.
Parapsyche apicalis
Parapsyche apicalis is a species of net-spinning caddisfly in the family Hydropsychidae, originally described as Arctopsyche apicalis by Banks in 1908. The species belongs to the subfamily Arctopsychinae and is found in North America. As a member of Hydropsychidae, larvae construct fixed retreats and capture nets to filter food particles from flowing water.
Paratendipes albimanus
Paratendipes albimanus is a non-biting midge species in the family Chironomidae, found in freshwater habitats across Europe and North America. The species has been studied for its life history and growth patterns in Michigan headwater streams. As a member of the Chironomidae, it completes its larval development in aquatic environments before emerging as an adult.
Parydra quadrituberculata
shore fly
Parydra quadrituberculata is a species of shore fly in the family Ephydridae, first described by Loew in 1862. Shore flies in this family are typically associated with aquatic or semi-aquatic habitats. The specific epithet 'quadrituberculata' suggests four tubercles, likely referring to a diagnostic morphological feature. The species has been documented in scientific literature including a study of its immature stages.
Pedomoecus sierra
Pedomoecus sierra is a species of caddisfly in the family Apataniidae, described by Ross in 1947. It is known from the Sierra Nevada region of California. Like other members of the order Trichoptera, the larvae are aquatic and construct protective cases from silk and environmental materials. The specific epithet 'sierra' refers to its type locality in the Sierra Nevada mountains.
Pelocoris biimpressus shoshone
Pahranagat Naucorid Bug
Pelocoris biimpressus shoshone is a subspecies of creeping water bug in the family Naucoridae, described by La Rivers in 1948. It belongs to the true bug order Hemiptera and is part of the aquatic true bug infraorder Nepomorpha. The subspecies is known from Middle and North America, with records indicating presence in both regions. Very limited observational data exists for this taxon, with only two observations recorded in iNaturalist.
Penelomax septentrionalis
Penelomax septentrionalis is a species of mayfly in the family Ephemerellidae, first described by McDunnough in 1925. It is native to the Nearctic region of North America. As a member of the order Ephemeroptera, it has a short-lived adult stage and aquatic nymphal development.
Pentagenia vittigera
riverbed burrower mayfly
Pentagenia vittigera is a riverbed burrower mayfly in the family Palingeniidae. The species was described by Walsh in 1862 and is native to North America. It is characterized by its burrowing lifestyle in riverbed substrates. The genus Pentagenia is distinguished from related mayflies by specific morphological features of the wing venation and genitalia.
Perlesta nitida
Tiny Stone
Perlesta nitida, commonly known as the tiny stone, is a species of stonefly in the family Perlidae. It was described by Banks in 1948. This species belongs to the order Plecoptera, a group of aquatic insects commonly known as stoneflies. The common name "tiny stone" reflects its small size relative to other stoneflies in the family.
Perlinella drymo
Striped Stone
Perlinella drymo, commonly known as the striped stone, is a stonefly species in the family Perlidae. It was first described by Newman in 1839 under the basionym Isogenus drymo. The species is distributed across eastern North America, with records from Alabama, Arkansas, Connecticut, Florida, Georgia, and other states. As a member of Perlidae, it belongs to a family of predatory stoneflies commonly referred to as common stoneflies.
Perlinella ephyre
Vernal Stone
Perlinella ephyre, commonly known as the vernal stone, is a species of common stonefly in the family Perlidae. It is found in North America, with records from the northeastern United States and several southeastern states including Alabama, Arkansas, Florida, and Georgia. As a member of Perlidae, it is likely a predatory stonefly, though specific ecological details remain poorly documented.
Perlinodes
Perlinodes is a genus of stoneflies in the family Perlodidae. It was established by Needham and Claassen in 1925 and is classified within the tribe Arcynopterygini. The genus is found in western North America, with records from Alberta and several western U.S. states. Like other perlodid stoneflies, members of this genus are aquatic as nymphs and terrestrial as adults.
Perlinodes aurea
Perlinodes aurea is a species of stonefly in the family Perlodidae. The genus Perlinodes is part of the subfamily Isoperlinae, a group of predatory stoneflies characterized by their streamlined bodies and aquatic larval stages. Like other members of Perlodidae, P. aurea has a life cycle tied to clean, well-oxygenated freshwater habitats. Adult stoneflies are generally short-lived and do not feed, focusing instead on reproduction. The specific epithet "aurea" (golden) likely refers to coloration characteristics of the species.
Perloidea
common stoneflies, perloid stoneflies
Perloidea is a superfamily of stoneflies within the suborder Arctoperlaria, characterized by well-developed mouthparts adapted for predation or omnivory. Members are primarily found in the Northern Hemisphere. The superfamily includes several families of medium to large-sized stoneflies with diverse ecological roles in freshwater ecosystems.
Phaedon viridis
watercress leaf beetle
Phaedon viridis, commonly known as the watercress leaf beetle, is a leaf beetle species in the family Chrysomelidae. It is native to North America and has been documented across multiple Canadian provinces including Alberta, British Columbia, and Manitoba. The species is associated with aquatic or semi-aquatic habitats where its host plants grow.
Phaenopsectra flavipes
Phaenopsectra flavipes is a non-biting midge in the family Chironomidae. It occurs across the Palearctic region, with records from Scandinavia, Denmark, and Slovakia. The species has been documented in pond habitats. As with other chironomids, adults are short-lived and do not feed.
Phaenopsectra obediens
Phaenopsectra obediens is a species of non-biting midge in the family Chironomidae, first described by Johannsen in 1905. It belongs to the tribe Chironomini within the subfamily Chironominae. The species has been documented in iNaturalist with 91 observations, indicating it is encountered with some frequency by naturalists.
Phaenopsectra profusa
Phaenopsectra profusa is a species of non-biting midge in the family Chironomidae, described by Townes in 1945. It belongs to the tribe Chironomini within the subfamily Chironominae. The species is rarely recorded, with limited observational data available.
Phaenopsectra punctipes
Phaenopsectra punctipes is a species of non-biting midge in the family Chironomidae, first described by Christian Rudolph Wilhelm Wiedemann in 1817. It belongs to the subfamily Chironominae and tribe Chironomini. The species is recorded from Europe, with confirmed presence in Denmark, Norway, and Sweden based on distribution records.