Aquatic-insect
Guides
Crocothemis
Scarlet Skimmers
Crocothemis is a genus of dragonflies in the family Libellulidae, subfamily Sympetrinae. Species occur across southern Europe, Africa, Asia, Australia, and the Southwest Pacific. These are small to medium-sized dragonflies known for bright coloration in males, ranging from vivid red to rich blue, while females are typically dull brown or orange. They are aerial predators that perch on vegetation near water and fly out to capture prey.
Cultus
Cultus is a genus of stoneflies in the family Perlodidae, established by Ricker in 1952. The genus belongs to the tribe Diploperlini and is part of the diverse Perlodinae subfamily within the order Plecoptera. Species in this genus are found in western North America.
Cultus verticalis
Spiny Springfly
Cultus verticalis, commonly known as the spiny springfly, is a species of stonefly in the family Perlodidae. The species was first described by Banks in 1920 under the basionym Perla verticalis. It is known from scattered localities in eastern North America, with confirmed records from Georgia, North Carolina, New Hampshire, Pennsylvania, and Québec. As a member of the Perlodidae, it belongs to a family of predatory stoneflies commonly found in cool, well-oxygenated streams.
Curicta scorpio
waterscorpion
Curicta scorpio is a species of waterscorpion in the family Nepidae. It occurs in Central America and North America, with a documented first record for Costa Rica on the Caribbean slope. Waterscorpions are aquatic true bugs characterized by their raptorial forelegs and breathing siphons.
Cylloepus
riffle beetles
Cylloepus is a genus of riffle beetles in the family Elmidae, first described by Erichson in 1847. The genus contains approximately six described species distributed across the Americas. Members are aquatic beetles associated with flowing water habitats. Species have been documented from North America, the Caribbean, and South America.
Cymatia
water boatmen
Cymatia is a genus of water boatmen in the family Corixidae, comprising approximately six described species. Members are aquatic true bugs inhabiting lentic waterbodies. The genus includes the neonative species Cymatia rogenhoferi, which has shown significant range expansion across Europe and the UK since 2005. Cymatia species are characterized by their tolerance of diverse environmental conditions and strong dispersal abilities.
Cymatia americana
water boatman
Cymatia americana is a species of water boatman in the family Corixidae, first described by Hussey in 1920. It belongs to the subfamily Cymatiinae and is one of several species in the genus Cymatia found in North America. Water boatmen in this family are aquatic true bugs that inhabit freshwater environments.
Cymatiainae
Cymatiainae is a subfamily of water boatmen within the family Corixidae. Members are aquatic insects adapted to freshwater habitats. The subfamily is distinguished by morphological features of the genitalia and wing venation. Cymatiainae represents one of several lineages within the diverse Corixidae family.
Cyrnellus
Cyrnellus is a genus of caddisflies in the family Polycentropodidae. Larvae of at least one species, C. fraternus, are specialized inhabitants of submerged wood (snags) in river systems, where they construct retreats. The genus was established by Nathan Banks in 1913. Species within this genus appear to exhibit specific microhabitat preferences related to flow conditions and substrate stability.
Cyrtobagous
salvinia weevil
Cyrtobagous is a genus of small weevils in the family Curculionidae, native to South America. The genus contains species specialized as biological control agents for invasive aquatic ferns in the genus Salvinia. C. salviniae has been introduced to multiple continents to manage giant salvinia (Salvinia molesta), while C. singularis has more limited effectiveness. Both species complete their life cycles within or on their host plants in aquatic environments.
Dactylolabis montana
Dactylolabis montana is a species of limoniid crane fly inhabiting madicolous environments in eastern North America. The species develops in thin water films on rock surfaces, with distinct larval and pupal stages described. It occurs from Ontario and Newfoundland south to Kansas, Arkansas, Mississippi, Tennessee, and South Carolina.
Dasycorixa rawsoni
Dasycorixa rawsoni is a species of water boatman described by Hungerford in 1948. It belongs to the family Corixidae, a group of aquatic true bugs adapted to life in freshwater environments. The species is known from North America and is classified within the tribe Glaenocorisini.
Demeijerea
Demeijerea is a genus of non-biting midges in the family Chironomidae, subfamily Chironominae. The genus was established by Kruseman in 1933 and contains four described species. Members of this genus are found in Europe, with distribution records from Denmark, Norway, and Sweden. Like other chironomids, the larvae are aquatic and the adults do not feed.
Demeijerea brachialis
Demeijerea brachialis is a species of non-biting midge in the family Chironomidae, first described by Coquillett in 1901. As a member of the tribe Chironomini, it belongs to one of the most diverse groups of aquatic insects. The genus Demeijerea is distinguished from related chironomid genera by specific morphological features of the adult male genitalia and larval structures.
Deuterophlebia shasta
Deuterophlebia shasta is a species of mountain midge in the family Deuterophlebiidae, first described by Wirth in 1951. This family represents one of the most primitive lineages of true flies (Diptera), with larvae that are highly specialized for life in cold, fast-flowing mountain streams. The species epithet 'shasta' refers to Mount Shasta in northern California, indicating the type locality. Deuterophlebiidae larvae are notable for their unusual body plan, featuring six pairs of ventral suckers that allow them to cling to rocks in torrential currents.
Dicosmoecinae
northern caddisflies
Dicosmoecinae is a subfamily of caddisflies within the family Limnephilidae, comprising approximately 19 genera and at least 80 described species. The group is commonly referred to as "northern caddisflies," reflecting its predominantly Holarctic distribution. The subfamily was established by Schmid in 1955, with Dicosmoecus as its type genus. Members are case-making caddisflies, with larvae constructing portable shelters from plant materials.
Dicosmoecus pallicornis
Dicosmoecus pallicornis is a species of caddisfly in the family Limnephilidae, described by Banks in 1943. It belongs to a genus of case-making caddisflies whose larvae construct portable cases from plant material. The species is documented from North America within the Nearctic region. As with other Limnephilidae, it likely has a holometabolous life cycle with aquatic larval stages and terrestrial adults.
Dicranopselaphus variegatus
variegated false water penny beetle
Dicranopselaphus variegatus is a species of water penny beetle in the family Psephenidae, commonly known as the variegated false water penny beetle. The species was described by George Henry Horn in 1880. Like other members of Psephenidae, adults are terrestrial while larvae are aquatic, living on submerged rocks and logs in flowing water. It is found in North America.
Dineutus nigrior
whirligig beetle
A species of whirligig beetle in the family Gyrinidae, found across North America. Adults are surface-dwelling aquatic beetles known for their distinctive circular swimming patterns and social aggregations on water. Males possess enlarged protarsal pads used during mating attempts, and accessory glands that show positive allometry associated with increased mating success. The species serves as host to water mites, with parasitism levels linked to host body condition and sex.
Dineutus serrulatus
whirligig beetle
Dineutus serrulatus is a species of whirligig beetle in the family Gyrinidae, first described by LeConte in 1868. The species occurs in the Appalachian Mountains of the southeastern United States, with records from northeastern Georgia and the southwestern Carolinas. A subspecies, D. s. analis, has been recorded from Kansas and the southeastern United States.
Dineutus sublineatus
whirligig beetle
Dineutus sublineatus is a species of whirligig beetle in the family Gyrinidae, found in Central America and the Southwestern United States. Like other members of its genus, it possesses two separate pairs of compound eyes—one pair viewing above and one below the water surface—an adaptation for simultaneous aerial and underwater vision. Neuroanatomical studies have shown this species exhibits a unique sensory modality switch: its mushroom body calyces, brain structures typically associated with olfactory processing in insects, receive exclusive visual input from the dorsal eye optic lobes rather than olfactory input.
Diphetor
Diphetor is a genus of small mayflies in the family Baetidae, established by Waltz and McCafferty in 1987. These insects belong to the order Ephemeroptera, characterized by their short adult lifespan and aquatic nymphal stages. The genus is part of the diverse Baetidae family, one of the largest families of mayflies.
Diphetor hageni
Hagen's Small Minnow Mayfly
Diphetor hageni is a small mayfly species in the family Baetidae, commonly known as Hagen's Small Minnow Mayfly. It is native to the Nearctic region, primarily distributed across North America. The species is part of the diverse Baetidae family, which are among the most abundant and widespread mayflies in running waters.
Diplectrona modesta
Diplectrona modesta is a species of netspinning caddisfly in the family Hydropsychidae, first described by Banks in 1908. It is native to North America, with documented occurrences in the Nearctic region including Vermont. The species has been studied for its life history and production dynamics in freshwater stream habitats, particularly in Walker Branch, Tennessee.
Diploperla
springflies
Diploperla is a genus of springflies (family Perlodidae) comprising five described species found in eastern North America. These stoneflies inhabit stream environments where their nymphs develop as predators in leaf packs and riffle areas. The genus exhibits univoltine life cycles with adult emergence occurring in spring.
Diura
Diura is a genus of stoneflies (Plecoptera) in the family Perlodidae, comprising approximately seven described species distributed across Europe and North America. Species such as Diura nanseni are univoltine, completing their life cycle in one year with nymphal growth primarily during spring months. Nymphs are typically associated with lotic environments and exhibit predatory or grazing feeding habits depending on species.
Dixella californica
Dixella californica is a species of meniscus midge in the family Dixidae (Order: Diptera). These small, delicate flies are associated with aquatic habitats where their larvae develop. The species was described by Johannsen in 1923 and is known from California. Dixidae larvae are recognized by their distinctive habit of hanging upside down from the water surface film, feeding on microorganisms and organic matter.
Dixella dorsalis
Dixella dorsalis is a species of midge in the family Dixidae, described by Garrett in 1924. Dixidae, commonly known as meniscus midges or dixid midges, are small non-biting flies closely related to mosquitoes (Culicidae). Larvae of this family are aquatic, typically inhabiting the surface film of standing water where they feed on microorganisms. The family is relatively small and understudied, with most species poorly known beyond basic taxonomic descriptions.
Djalmabatista pulcher
Djalmabatista pulcher is a species of non-biting midge in the family Chironomidae, subfamily Tanypodinae, tribe Procladiini. First described by Johannsen in 1908, this species belongs to a genus of predatory midges whose larvae inhabit aquatic environments. The genus Djalmabatista is part of the diverse chironomid fauna, with this particular species having documented occurrence records from Brazil (São Paulo state).
Dolophilodes dorca
Dolophilodes dorca is a species of caddisfly in the family Philopotamidae. Members of this genus are small, slender caddisflies associated with lotic (flowing water) habitats. The larvae construct silken retreats and capture nets for feeding on fine particulate organic matter. Like other philopotamids, adults are typically nocturnal and are attracted to light.
Doroneuria baumanni
Cascades Stonefly, cascades stone
Doroneuria baumanni, known as the Cascades Stonefly, is a species of common stonefly in the family Perlidae. It was described by Stark & Gaufin in 1974. The species occurs in western North America, with documented records from British Columbia, Washington, Oregon, California, and Nevada. Like other Perlidae, it is predatory in its aquatic nymph stage.
Drunella coloradensis
Small Western Green Drake
Drunella coloradensis is a species of spiny crawler mayfly in the family Ephemerellidae, commonly known to anglers as the Small Western Green Drake. The species is found in freshwater streams across western North America, with a range extending from Alaska and northern Canada through the western United States to northern Mexico and Central America. Nymphs are known to alter their behavior in response to short-term pH reductions, becoming more active under acidic conditions. The species is of particular importance to fly fishermen, who imitate its various life stages with artificial flies.
Drunella cornutella
spiny crawler mayfly
Drunella cornutella is a species of spiny crawler mayfly in the family Ephemerellidae, originally described by McDunnough in 1931 as Ephemerella cornutella. It is found in North America, with records from the Nearctic region including the northeastern United States. Like other members of the genus Drunella, it is an aquatic insect with immature stages living in freshwater habitats.
Drunella doddsii
Western Green Drake
Drunella doddsii is a species of spiny crawler mayfly in the family Ephemerellidae, commonly known as the Western Green Drake. Originally described as Ephemerella doddsi by Needham in 1927, this species is significant to fly fishing communities in western North America. The species is part of the diverse Drunella genus, which includes other notable green drake species such as D. grandis.
Drunella grandis
Western Green Drake, Green Drake, Spinner Green Drake
Drunella grandis is a species of spiny crawler mayfly in the family Ephemerellidae. It is commonly known as the Western Green Drake among fly fishermen, who highly value this species for its importance as a trout food source. The species is native to North America and has been documented with three recognized subspecies. Adults are notable for their large size and greenish coloration, making them a prominent feature of western North American streams.
Drunella lata
Drunella lata is a species of spiny crawler mayfly in the family Ephemerellidae. It was first described by Morgan in 1911. The species is found in North America and belongs to a genus commonly known as "green drakes" among fly fishermen. Like other members of Ephemerellidae, it has aquatic nymphs and winged adults.
Drunella pelosa
Drunella pelosa is a species of spiny crawler mayfly in the family Ephemerellidae. It is native to North America. As a member of the Ephemerellidae family, it shares characteristics with other spiny crawler mayflies, including a robust body form and adaptations for clinging to substrates in flowing water. The species was originally described as Ephemerella pelosa by Mayo in 1952.
Drunella spinifera
Western Slate Olive
Drunella spinifera is a species of spiny crawler mayfly in the family Ephemerellidae. It is found in southwestern and northern Canada, the western United States, and Alaska. The common name "Western Slate Olive" reflects its regional distribution and likely coloration. Like other members of the genus Drunella, it belongs to a group of mayflies commonly targeted by fly fishermen, though specific angling references for this species are limited.
Drunella tuberculata
spiny crawler mayfly
Drunella tuberculata is a species of spiny crawler mayfly in the family Ephemerellidae, described by Morgan in 1911. It is found in North America and is closely related to D. allegheniensis, from which it can be distinguished by specific morphological characters. The species is part of a group of mayflies important to fly fishermen, where nymphs and adults serve as significant food sources for trout and other sport fish.
Drunella walkeri
Small Blue-winged Olive
Drunella walkeri is a species of spiny crawler mayfly in the family Ephemerellidae, commonly known as the Small Blue-winged Olive among anglers. It is found in North America and is one of the mayfly species frequently imitated by fly fishermen. The species was first described by Eaton in 1884.
Dubiraphia brevipennis
Dubiraphia brevipennis is a species of riffle beetle in the family Elmidae, described by Hilsenhoff in 1973. Like other elmid beetles, it is adapted to life in flowing water environments. The species is known from North America, though specific details about its biology and ecology remain limited in the available literature.
Dysmicohermes
Dysmicohermes is a genus of fishflies in the family Corydalidae, established by Munroe in 1953. The genus contains two described species: Dysmicohermes disjunctus and Dysmicohermes ingens. As members of Megaloptera, these insects represent a relatively small and ancient order of holometabolous insects. The genus is part of the diverse Corydalidae family, which includes some of the largest aquatic insects in North America.
Dytiscus verticalis
Vertical Diving Beetle
Dytiscus verticalis is a species of predaceous diving beetle in the family Dytiscidae. As a member of the genus Dytiscus, it is among the largest diving beetles in North America. The species inhabits freshwater aquatic systems and, like other members of its genus, is an active predator in both larval and adult stages. The specific epithet 'verticalis' refers to a characteristic morphological feature of this species.
Enallagma exsulans
Stream Bluet
Enallagma exsulans, commonly known as the Stream Bluet, is a species of damselfly in the family Coenagrionidae. It is distinguished from many other bluet species by its strong association with flowing water rather than still ponds and lakes. The species ranges across much of eastern and central North America.
Endochironomus subtendens
Endochironomus subtendens is a species of non-biting midge in the family Chironomidae, originally described as Tanytarsus subtendens by Townes in 1945. The species was later transferred to the genus Endochironomus. Like other members of this genus, it is an aquatic insect with larval stages developing in freshwater habitats. The genus Endochironomus is known for larvae that construct portable cases using silk and environmental materials.
Enochrus sayi
Enochrus sayi is a species of water scavenger beetle in the family Hydrophilidae. It occurs across much of eastern and central North America, with introduced populations in the Hawaiian Islands. The species inhabits freshwater aquatic environments.
Epeorus deceptivus
flatheaded mayfly
Epeorus deceptivus is a species of flatheaded mayfly in the family Heptageniidae. First described by McDunnough in 1924, it was originally placed in the genus Cinygma before being transferred to Epeorus. It is found in North America.
Epeorus fragilis
flatheaded mayfly
Epeorus fragilis is a species of flatheaded mayfly in the family Heptageniidae, first described by Morgan in 1911. It is distributed across North America. As a member of the order Ephemeroptera, it undergoes aquatic larval development before emerging as a short-lived adult.
Epeorus longimanus
flatheaded mayfly
Epeorus longimanus is a flatheaded mayfly species in the family Heptageniidae. Nymphs inhabit stream riffles and show specific microhabitat preferences, being more abundant in areas with smaller sediment sizes, higher live periphyton biomass, and lower densities of invertebrate predators. The species is distributed across western North America from Alaska through the western United States to southwestern and northern Canada.
Epeorus pleuralis
Quill Gordon
Epeorus pleuralis, commonly known as the Quill Gordon, is a flatheaded mayfly in the family Heptageniidae. It is native to North America and is recognized as an important species in aquatic entomology and fly fishing. The species is known for its relatively early emergence in the spring, making it a significant hatch for anglers in eastern North American streams.