Mayfly
Guides
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.
Paraleptophlebia vaciva
pronggilled mayfly
Paraleptophlebia vaciva is a species of pronggilled mayfly in the family Leptophlebiidae. It is found in southwestern Canada, the northwestern United States, and Alaska. As a member of Leptophlebiidae, it possesses the characteristic forked gills on abdominal segments that give the group its common name.
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.
Pisciforma
Pisciforma is a suborder of mayflies (Ephemeroptera) encompassing at least 410 described species across 11 families. It includes diverse aquatic insects commonly known as minnow mayflies, flatheaded mayflies, and sand-dwelling mayflies. Members occupy varied freshwater habitats and exhibit morphological diversity in mouthpart structure and leg morphology.
Plauditus cestus
Plauditus cestus is a small mayfly in the family Baetidae, widespread across eastern and central North America. Recent records have extended its known range substantially, including a 1900 km northwestward expansion to the Northwest Territories. The species exhibits notable larval color variation, with some populations showing pronounced abdominal segment coloration.
Plauditus dubius
small minnow mayfly
Plauditus dubius is a species of small minnow mayfly in the family Baetidae. It has been documented across a broad geographic range including all of Canada, the northern and southeastern United States, and Alaska. The species belongs to a genus of mayflies commonly associated with running water habitats. Limited observational records exist, with only three documented observations in iNaturalist.
Procloeon nelsoni
Procloeon nelsoni is a species of small minnow mayfly in the family Baetidae, described by Wiersema in 1999. It is known from the southern United States. As a member of Baetidae, it belongs to a diverse family of mayflies commonly associated with running water habitats.
Procloeon vicinum
Procloeon vicinum is a species of small minnow mayfly in the family Baetidae. It belongs to a genus of mayflies commonly found in freshwater habitats across North America. The species was described by Hagen in 1861 and is currently accepted as valid. Like other members of Baetidae, it likely inhabits running waters and exhibits the typical mayfly life cycle of aquatic nymphal stages followed by short-lived winged adults.
Procloeon viridoculare
small minnow mayfly
Procloeon viridoculare is a species of small minnow mayfly in the family Baetidae. It was first described by Berner in 1940 under the basionym Centroptilum viridocularis. The species is known from North America. Like other members of Baetidae, it belongs to a diverse family of mayflies commonly associated with freshwater habitats.
Pseudiron
crabwalker mayflies
Pseudiron is a monotypic genus of mayflies containing a single described species, Pseudiron centralis. The genus is notable for its specialized psammophilous (sand-dwelling) ecology and predatory lifestyle, which is uncommon among mayflies. Larvae are active epibenthic predators that inhabit sandy substrates in river systems.
Pseudironidae
crabwalker mayflies
Pseudironidae is a monotypic family of mayflies containing a single genus, Pseudiron, with one described species, Pseudiron centralis. These insects are commonly referred to as crabwalker mayflies, a name reflecting their distinctive locomotion. The family represents a rare example of extreme taxonomic reduction in Ephemeroptera, with its entire diversity contained within one species.
Raptoheptagenia cruentata
predaceous flat-headed mayfly
Raptoheptagenia cruentata is a mayfly species originally described as Heptagenia cruentata by Walsh in 1863, later reclassified into the new genus Raptoheptagenia based on distinctive larval morphology. The genus was established because the larvae differ markedly from other Heptagenia species, having been previously misidentified as belonging to the genus Anepeorus. Adult males were successfully reared from these larvae, confirming the adult-larval association. This species belongs to the family Heptageniidae, commonly known as flat-headed mayflies.
Rhithrogena hageni
Western Black Quill
Rhithrogena hageni is a mayfly species in the family Heptageniidae, first described by Eaton in 1885. It is known from the Nearctic region, specifically North America. The species is commonly referred to as the Western Black Quill. Like other members of the genus Rhithrogena, it is associated with lotic (flowing water) habitats where its nymphs develop.
Serratella levis
spiny crawler mayfly
Serratella levis is a species of spiny crawler mayfly in the family Ephemerellidae. It was described by Day in 1954 and is found in North America, specifically in the western United States. As a member of the spiny crawler mayflies, it belongs to a group characterized by distinctive morphological features and ecological adaptations to freshwater habitats.
Serratella serrata
little sooty olive
Serratella serrata is a species of spiny crawler mayfly in the family Ephemerellidae. It is found in the south half of Canada and the eastern United States. The species is commonly known as the little sooty olive.
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.
Siphlonurus
primitive minnow mayflies, gray drakes
Siphlonurus is a genus of primitive minnow mayflies in the family Siphlonuridae, comprising more than 40 described species. Species inhabit temporary and intermittent ponds, with nymphal development occurring during spring months and adult emergence in late May to June. Adults are non-feeding and rely on energy reserves accumulated during the aquatic larval stage. The genus is notable among fly fishers for species such as Siphlonurus quebecensis (early brown quill), which is imitated with specialized fly patterns.
Siphlonurus alternatus
Northern Summer Mayfly
Siphlonurus alternatus is a primitive minnow mayfly with a Holarctic distribution spanning North America and Europe. The species is univoltine, overwintering as eggs and emerging as adults between May and August. Larvae inhabit deep pools in rivers, streams, and calcareous lakes, where they feed on fine particulate organic detritus. Adults emerge during daylight hours, with males forming swarms at dawn and dusk.
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 marshalli
primitive minnow mayfly
Siphlonurus marshalli is a species of primitive minnow mayfly in the family Siphlonuridae, described by Traver in 1934. It is found in North America. As a member of the family Siphlonuridae, it represents one of the more basal lineages within the order Ephemeroptera.
Siphlonurus mirus
primitive minnow mayfly
Siphlonurus mirus is a species of primitive minnow mayfly in the family Siphlonuridae. It has been studied in intermittent pond habitats, where its life history is synchronized to seasonal wet-dry cycles. The species is found in North America and belongs to a family of mayflies known for their importance to fly fishing.
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.
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.
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 floridense
Stenacron floridense is a species of flatheaded mayfly in the family Heptageniidae, first described by Lewis in 1974. It is part of a genus of mayflies characterized by dorsoventrally flattened bodies adapted for clinging to substrates in flowing water. The species is recorded from North America, though specific details about its biology remain limited in published literature.
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.
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.
Stenonema femoratum
Dark Cahill
Stenonema femoratum, commonly known as the Dark Cahill, is a mayfly species in the family Heptageniidae. It is native to North America and has been documented in the Nearctic region, including the northeastern United States. The species is part of the diverse mayfly fauna associated with freshwater systems.
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.
Tricorythodes explicatus
Tricorythodes explicatus is a species of small mayfly in the family Leptohyphidae, first described by Eaton in 1892. It belongs to a genus commonly known as stout crawler mayflies, characterized by reduced wing venation and robust body proportions. The species has been documented in Middle America and North America, though detailed biological studies remain limited.
Tsalia
Tsalia is a genus of mayflies in the family Ephemerellidae, established by Jacobus and McCafferty in 2008. The genus is poorly documented in scientific literature, with minimal published information on its species composition, biology, or ecology. As a member of Ephemerellidae, it belongs to a family commonly known as spiny-crawler mayflies, though genus-specific traits remain largely uncharacterized.
Tsalia berneri
Tsalia berneri is a species of mayfly in the family Ephemerellidae, originally described as Ephemerella berneri by Allen & Edmunds in 1958. The genus Tsalia was later established to accommodate this and related species based on distinctive morphological features. This Nearctic species is known from limited records in North America. Like other members of Ephemerellidae, it is a small to medium-sized mayfly with aquatic nymphal stages.