Aquatic-insect
Guides
Pycnopsyche scabripennis
giant red sedge
Pycnopsyche scabripennis, commonly known as the giant red sedge, is a northern caddisfly in the family Limnephilidae. Larvae inhabit allochthonous organic materials in stream environments. The species exhibits rapid larval growth followed by early aestivation and emergence, a temporal pattern that reduces competition with congeners. Adult males display distinct peak arrival times at light sources when active alongside related species, suggesting temporal partitioning as a coexistence mechanism.
Pycnopsyche virginica
Virginia Caddisfly
Pycnopsyche virginica is a species of caddisfly in the family Limnephilidae, first described by Nathan Banks in 1900. It is native to North America within the Nearctic region. As a member of the genus Pycnopsyche, it belongs to a group of case-making caddisflies whose larvae construct portable cases from plant material. The species is part of the diverse Limnephilidae family, which contains many species with aquatic larval stages and terrestrial adults.
Radotanypus
Radotanypus is a genus of non-biting midges (Chironomidae) established by Fittkau and Murray in 1985. The genus belongs to the subfamily Tanypodinae, a group of predatory midges whose larvae inhabit aquatic environments. Species-level taxonomy remains poorly documented in public sources.
Ranatra brevicollis
Western Waterscorpion
Ranatra brevicollis is a species of waterscorpion in the family Nepidae, first described by Montandon in 1910. It is distributed across Central America and North America. The species belongs to a genus of aquatic predatory insects commonly known as waterscorpions due to their elongated, scorpion-like appearance. It is recognized by the common name Western Waterscorpion.
Ranatra buenoi
waterscorpion
Ranatra buenoi is a species of waterscorpion in the family Nepidae, described by Hungerford in 1922. It occurs in North America. Waterscorpions in this genus are aquatic predatory insects characterized by elongated bodies and raptorial forelegs. The specific epithet honors an individual, though the source context does not clarify the namesake.
Ranatra nigra
Ranatra nigra is a waterscorpion species in the family Nepidae, occurring in aquatic environments of the Mobile/Tensaw Delta. The species has been documented in association with the water mite Hydrachna magniscutata, which exhibits temporal distribution patterns linked to R. nigra. As a member of the genus Ranatra, it possesses the elongated body form and raptorial forelegs characteristic of waterscorpions.
Rhagovelia plumbea
Rhagovelia plumbea is a species of small water strider in the family Veliidae, first described by Uhler in 1894. It is one of the most widespread members of its genus, occurring across the Caribbean, Central America, North America, and South America. The species inhabits freshwater surface habitats where it uses the water surface tension to move.
Rhagovelia rivale
smaller water strider
Rhagovelia rivale is a species of water strider in the family Veliidae, first described by Torre-Bueno in 1924. It belongs to the genus Rhagovelia, a group of smaller water striders characterized by their ability to skate on water surfaces using modified legs. The species is documented from North America, though specific details about its ecology and distribution within that range remain limited in available sources.
Rheumatobates tenuipes
Rheumatobates tenuipes is a water strider in the family Gerridae, first described by Meinert in 1895. It belongs to the subfamily Rhagodotarsinae, a group characterized by specialized adaptations for life on the water surface. The species occurs in North and Middle America. Like other gerrids, it occupies the air-water interface, exploiting surface tension to move and forage.
Rhionaeschna californica
California Darner
Rhionaeschna californica, the California darner, is a medium-sized dragonfly in the family Aeshnidae. Adults are distinguished by bright blue diagonal spots on the abdomen and exhibit sexual dimorphism in coloration and eye color. The species occupies aquatic habitats across western North America and Central America, with larvae requiring several years of aquatic development before nocturnal emergence as adults.
Rhopalosiphum nymphaeae
waterlily aphid, water lily aphid
Rhopalosiphum nymphaeae, the waterlily aphid, is a cosmopolitan, host-alternating aphid species with a unique ability to thrive in both aquatic and terrestrial environments. It is a significant agricultural pest that damages crops through direct herbivory and as a vector for plant viruses, particularly affecting Prunus spp. fruits and various aquatic plants. The species exhibits complex life history traits including rapid population growth (intrinsic rate of increase 0.315 day⁻¹, doubling time 2.2 days) and strong host preferences among aquatic vegetation.
Rhyacophila
caseless caddisflies
Rhyacophila is a large genus of caddisflies (Trichoptera) in the family Rhyacophilidae, comprising at least 640 described species. The genus is cosmopolitan in distribution, with significant diversity in Europe, Asia, and North America. Larvae are commonly known as 'caseless caddis' because they do not construct portable cases, instead using silk to anchor themselves to substrates in running water. The genus exhibits high endemism in certain regions, with multiple species restricted to specific mountain ranges or islands.
Rhyacophila acutiloba
Rhyacophila acutiloba is a species of free-living caddisfly in the family Rhyacophilidae, first described by Morse & Ross in 1971. As a member of the genus Rhyacophila, it belongs to a group commonly known as "caseless caddis" or "free-living caddisflies" whose larvae do not construct portable cases. The species is known from North America, with records from Vermont and other parts of the Nearctic region. Like other rhyacophilids, it is associated with lotic (flowing water) habitats.
Rhyacophila angelita
Rhyacophila angelita is a species of free-living caddisfly described by Banks in 1911. It belongs to the family Rhyacophilidae, a group characterized by predatory larvae that do not construct portable cases. The species is known from North America.
Rhyacophila formosa
Rhyacophila formosa is a species of free-living caddisfly first described by Nathan Banks in 1911. As a member of the family Rhyacophilidae, it belongs to a group of caddisflies whose larvae do not construct portable cases, instead living freely on rocky substrates in freshwater habitats. The species is known to occur in North America.
Rhyacophila grandis
Rhyacophila grandis is a species of free-living caddisfly in the family Rhyacophilidae, first described by Banks in 1911. Unlike many caddisflies, it does not construct portable cases as larvae. The species is documented from North America, though specific details about its biology and ecology remain limited in the available literature.
Rhyacophila oreta
Rhyacophila oreta is a species of caseless caddisfly in the family Rhyacophilidae, described by Ross in 1941. It belongs to a genus whose larvae are free-living predators in freshwater habitats, constructing no protective cases. The species is known from North America in the Nearctic region. As with other Rhyacophila species, the larvae are aquatic and the adults are terrestrial, short-lived, and primarily reproductive in function.
Rhyacophilidae
Free-living Caddisflies
Rhyacophilidae is a family of caddisflies (Trichoptera) commonly known as free-living caddisflies. Larvae are distinctive for not constructing portable cases, instead living freely on substrates in freshwater habitats. Most species are predatory. The family contains over 700 described species, with the genus Rhyacophila alone comprising approximately 500 species distributed primarily across the Northern Hemisphere.
Salmoperla
Salmoperla is a genus of stoneflies (Plecoptera) in the family Perlodidae, tribe Arcynopterygini. Described in 1987 by Baumann and Lauck, this genus is known from California. As a member of the Systellognatha, Salmoperla belongs to a group of predatory stoneflies characterized by specialized mouthpart adaptations.
Scatella arizonensis
Scatella arizonensis is a species of shore fly in the family Ephydridae, described by Cresson in 1935. The genus Scatella comprises small flies commonly associated with aquatic or semi-aquatic habitats. As a member of the Ephydridae, this species is part of a diverse family of true flies adapted to various wet environments. Very few specific details are documented about this particular species beyond its taxonomic description.
Sepedon gracilicornis
snail-killing fly
Sepedon gracilicornis is a species of snail-killing fly in the family Sciomyzidae, described by Orth in 1986. It belongs to a genus of approximately twenty North American species whose larvae are obligate predators of aquatic pulmonate snails. The species has been documented through limited observations, with records indicating presence in wetland and aquatic edge habitats.
Sepedon tenuicornis
marsh fly
Sepedon tenuicornis is a species of marsh fly in the family Sciomyzidae, first described by Cresson in 1920. Like other members of the genus Sepedon, this species has aquatic predatory larvae that feed on pulmonate snails. The genus comprises approximately 20 recognized species in North America, arranged into species groups based on shared morphological characteristics. Adults are slender flies with elongated bodies, concave faces, and prominent antennae.
Serratella serratoides
spot-bellied spiny crawler mayfly
Serratella serratoides is a species of spiny crawler mayfly in the family Ephemerellidae. It was originally described as Ephemerella serratoides by McDunnough in 1931 before being transferred to the genus Serratella. The species is known from North America.
Sialis iola
Sialis iola is a species of alderfly described by Ross in 1937. As a member of the family Sialidae, it belongs to the order Megaloptera, a small group of aquatic insects closely related to dobsonflies and fishflies. The species is known to occur in North America, though specific details about its biology and ecology remain poorly documented. Like other alderflies, its larvae are presumed to be aquatic predators in freshwater habitats.
Sialis itasca
Sialis itasca is a species of alderfly in the family Sialidae, described by Ross in 1937. As a member of the order Megaloptera, it belongs to a small group of primitive holometabolous insects. The species is known from North America, with minimal observational records available. Like other alderflies, adults are associated with riparian habitats near the aquatic environments where their larvae develop.
Sialis mohri
alderfly
Sialis mohri is a species of alderfly in the family Sialidae, described by Ross in 1937. It is found in North America. Like other alderflies, it belongs to the order Megaloptera, a small group of aquatic insects whose larvae are predatory and develop in freshwater habitats. The species name honors Dr. Charles Mohr, an entomologist who collected the type specimens.
Sialis nevadensis
Sialis nevadensis is a species of alderfly in the family Sialidae, order Megaloptera. It was described by K. Davis in 1903 and is native to North America. The genus Sialis comprises aquatic insects whose larvae are predatory and develop in freshwater environments. Adults are typically found near streams and rivers during their brief aerial phase.
Sigara alternata
water boatman
Sigara alternata is a species of water boatman in the family Corixidae. It inhabits lentic aquatic environments in North America. Laboratory studies demonstrate that its egg development and growth rates are strongly influenced by thermal conditions, with developmental acceleration occurring at daily temperature maxima exceeding 15.0°C and a critical temperature threshold of 11.0–12.5°C required for egg-laying initiation.
Sigara bradleyi
Sigara bradleyi is a species of water boatman in the family Corixidae, first described by Abbott in 1913. As a member of the genus Sigara, it belongs to a diverse group of aquatic insects commonly found in freshwater habitats. The species is known to occur in North America and the Caribbean, though detailed biological information remains limited. Like other corixids, it likely inhabits ponds, lakes, and slow-moving waters where it occupies the benthic zone.
Sigara hubbelli
Sigara hubbelli is a species of water boatman in the family Corixidae, described by Hungerford in 1928. It belongs to the genus Sigara, a diverse group of aquatic true bugs found in freshwater habitats. The species is documented from North America, though detailed ecological and biological information remains limited in available sources.
Sigara hydatotrephes
Sigara hydatotrephes is a species of water boatman in the family Corixidae. It belongs to the large genus Sigara, which contains numerous species of aquatic insects found in freshwater habitats. The species was described by Kirkaldy in 1908. Like other corixids, it is adapted to life in water with modified hind legs for swimming.
Sigara lineata
Sigara lineata is a species of water boatman in the family Corixidae. It is found in North America. Water boatmen are aquatic insects that inhabit freshwater environments.
Sigara mississippiensis
Sigara mississippiensis is a species of water boatman in the family Corixidae, described by Hungerford in 1942. As a member of the genus Sigara, it belongs to a diverse group of aquatic true bugs commonly found in freshwater habitats across North America. The species is poorly documented in public scientific literature, with minimal observational records available.
Sigara omani
Sigara omani is a species of water boatman in the family Corixidae, first described by Hungerford in 1930. Despite its specific epithet suggesting a connection to Oman, the species is native to North America. Water boatmen in this genus are aquatic insects that inhabit freshwater environments. Available information about this particular species is limited.
Sigara ornata
ornate water boatman
Sigara ornata is a species of water boatman (family Corixidae) found in North America. Water boatmen are aquatic true bugs that inhabit freshwater environments, where they are known for their oar-like hind legs adapted for swimming. The specific epithet "ornata" suggests distinctive patterning or markings, though detailed morphological descriptions for this species are limited in available sources.
Sigara sigmoidea
Sigara sigmoidea is a species of water boatman in the family Corixidae, described by Abbott in 1913. The species name 'sigmoidea' refers to an S-shaped or sigma-like characteristic, likely of the male genitalia or abdominal structure, a common naming convention in this genus. Like other Corixidae, it is an aquatic insect inhabiting freshwater environments. The genus Sigara is one of the most species-rich genera of water boatmen in the Northern Hemisphere.
Sigara virginiensis
Sigara virginiensis is a species of water boatman in the family Corixidae, first described by Hungerford in 1948. Water boatmen are aquatic true bugs characterized by their oar-like hind legs adapted for swimming. This species is known from North America, though specific details about its biology and ecology remain limited in the available literature.
Simulium fibrinflatum
Inflated Gnat
Simulium fibrinflatum, commonly known as the inflated gnat, is a species of black fly in the family Simuliidae. It was described by Twinn in 1936. As a member of the genus Simulium, it shares the typical characteristics of black flies, including small size and aquatic larval development in flowing water. No species-specific biological details have been documented in the available sources.
Simulium longithallum
black fly
Simulium longithallum is a species of black fly in the family Simuliidae, described by Díaz Nájera and Vulcano in 1962. Black flies in this genus are small, blood-feeding dipterans with aquatic larval and pupal stages. Females require blood meals for egg development, while males do not feed on blood. The species is part of a diverse genus containing numerous vectors of disease agents affecting birds and mammals.
Siphlonurus columbianus
Columbian gray drake
Siphlonurus columbianus is a species of mayfly in the family Siphlonuridae, described by James Halliday McDunnough in 1925. It is native to the Nearctic region and is one of several Siphlonurus species known to fly fishermen as "gray drakes." Adults are medium-sized mayflies with distinctive body segmentation. Like other members of its genus, it has a two-winged adult stage and an aquatic nymphal stage. The species is occasionally referenced in angling literature, though detailed biological studies appear limited.
Siphlonurus occidentalis
primitive minnow mayfly
Siphlonurus occidentalis is a species of primitive minnow mayfly in the family Siphlonuridae. It belongs to a group of mayflies considered evolutionarily basal within the order Ephemeroptera. The species has a broad distribution spanning from Central America through North America, including Alaska and northern Canada. Like other members of its family, it likely inhabits cool, flowing waters and exhibits the characteristic aquatic nymph and terrestrial adult life stages typical of mayflies.
Siphlonurus phyllis
primitive minnow mayfly
Siphlonurus phyllis is a species of primitive minnow mayfly in the family Siphlonuridae. It was described by McDunnough in 1923. The species is distributed across all of Canada and the northern United States.
Siphlonurus quebecensis
early brown quill mayfly, gray drake
Siphlonurus quebecensis is a species of primitive minnow mayfly in the family Siphlonuridae. It occurs in North America and is known to anglers as the 'early brown quill' or 'gray drake,' a name reflected in fly-fishing patterns designed to imitate its adult form. The species is part of a group of mayflies whose aquatic nymphs and winged adults serve as important prey for trout and other sport fish.
Siphlonurus rapidus
Siphlonurus rapidus is a species of primitive minnow mayfly in the family Siphlonuridae. It was described by McDunnough in 1924. The species is found in North America. Like other members of the genus Siphlonurus, it is considered a "gray drake" mayfly of interest to fly fishermen.
Siphlonurus securifer
primitive minnow mayfly
Siphlonurus securifer is a species of primitive minnow mayfly described by McDunnough in 1926. It belongs to the family Siphlonuridae, a group of mayflies characterized by their relatively unspecialized morphology compared to more derived mayfly families. The species is known from North America, though specific details about its biology and ecology remain limited in published literature.
Siphlonurus spectabilis
primitive minnow mayfly
Siphlonurus spectabilis is a species of primitive mayfly in the family Siphlonuridae, first described by Traver in 1934. It belongs to a group commonly known as minnow mayflies, characterized by their relatively primitive morphological features compared to other mayfly families. The species has a documented distribution in northern Canada and the western United States.
Siphlonurus typicus
primitive minnow mayfly
Siphlonurus typicus is a species of primitive minnow mayfly in the family Siphlonuridae. It inhabits temporary ponds in eastern North America, where nymphs develop from March through June and adults emerge from late May to mid-June. Development is strongly temperature-dependent, with degree days serving as an excellent predictor of population maturity.
Siphloplecton basale
Siphloplecton basale is a cleftfooted minnow mayfly in the family Metretopodidae. It is the most widely distributed species in its genus, occurring across all of Canada and the eastern United States. The species belongs to a small family of mayflies characterized by specialized leg adaptations. Like other mayflies, it has an aquatic larval stage and a short-lived adult stage.
Sisyra apicalis
spongillafly
Sisyra apicalis is a species of spongillafly in the family Sisyridae, first described by Banks in 1908. Spongillflies are a small family of aquatic insects with specialized larval biology tied to freshwater sponges. The species has a broad Neotropical and Nearctic distribution, spanning from North America through Central America and the Caribbean to South America, with documented records across Brazil including the semiarid Caatinga biome.
Sisyra vicaria
spongillafly
Sisyra vicaria is a species of spongillafly (family Sisyridae) found in North America. Spongillaflies are small, delicate neuropteran insects whose larvae are obligate associates of freshwater sponges (Porifera), feeding on the sponge tissue. The species was originally described by Francis Walker in 1853 as Hemerobius vicarius. As with other members of the genus Sisyra, the adults are typically nocturnal and attracted to light.