Mayflies
Order Ephemeroptera
The Mayflies (Order Ephemeroptera) includes 387 species across 22 families and 82 genera in our directory.
About Mayflies
Ephemeroptera (mayflies) includes ~3,500 described species. Adult mayflies are famous for their extraordinarily short lifespans - some species live as adults for only 5 minutes to 24 hours, the shortest adult lifespan of any insect.
Economic Impact
Mayfly hatches are so massive they appear on weather radar - a 2014 Mississippi River hatch near La Crosse, Wisconsin was tracked by the National Weather Service. Mass emergences can cause slippery road conditions and traffic hazards.
Ecological Role
Mayfly nymphs spend 1-2 years developing in freshwater before emerging as adults. They are key bioindicators - their presence indicates clean, well-oxygenated water. They are also a primary food source for freshwater fish.
Families in Ephemeroptera (22)
Species in Ephemeroptera (387)
Callibaetis pictus
Callibaetis pictus
Identification: This species has a distinctive pale (usually W-shaped) dorsal marking on tergite 6, and all but the very darkest specimens (usually males) also have those markings on tergites 5 and 9. --Lloyd Gonzales
Early Brown Spinner
Leptophlebia cupida
Identification: Rusty red to dark brown, fore legs dark and other legs light, brownish wings, short middle tail, and small hindwing that sticks outward.
Epeorus pleuralis
Epeorus pleuralis
"This species is the first Eastern Epeorus to emerge each season, and is also one of the most famous mayflies in American fly-fishing literature. It is known as the "quill Gordon," and it was named for a fly pattern created by Theodore Gordon - the C
Hexagenia bilineata
Hexagenia bilineata
Identification: "two dark spots in the disk of the hindwing are characters of Hexagenia bilineata " (comment by Lloyd Gonzales on this image )
Maccaffertium smithae
Maccaffertium smithae
Identification: "From everything I have read the only possible species that fits this sample is (Maccaffertium smithae) it also has the right geographical range. The fact that the spiracular spots are well above the spirical folds and it has the medi
Neoephemera purpurea
Neoephemera purpurea
Identification: Projections on anterolateral margin of mesonotum pronounced
Stenacron interpunctatum
Stenacron interpunctatum
Identification: ID is very difficult. They cannot be ID'd reliably based upon tergal or sternal coloration. Removal of the left mandible and both maxillae are required for proper ID. The setae on the maxilla are commonly missing or broken so close in
Stenonema femoratum
Stenonema femoratum
Identification: Adults have a combination of four diagnostic traits: (adapted from comment by Lloyd Gonzales here ) male: female:
Ameletus amador
Ameletus amador
Ameletus andersoni
Ameletus andersoni
Ameletus cooki
Ameletus cooki
Ameletus costalis
Ameletus costalis
Ameletus dissitus
Ameletus dissitus
Ameletus doddsianus
Ameletus doddsianus
Ameletus montanus
Ameletus montanus
Ameletus suffusus
Ameletus suffusus
Ameletus tarteri
Ameletus tarteri
Ametropus fragilis
Ametropus fragilis
Arthroplea congener
Arthroplea congener
Baetisca becki
Baetisca becki
Baetisca callosa
Baetisca callosa
Baetisca carolina
Baetisca carolina
Baetisca columbiana
Baetisca columbiana
Baetisca escambiensis
Baetisca escambiensis
Baetisca gibbera
Baetisca gibbera
Baetisca obesa
Baetisca obesa
Baetisca rubescens
Baetisca rubescens
Caenis bajaensis
Caenis bajaensis
Caenis beskidensis
Caenis beskidensis
Caenis brevipes
Caenis brevipes
Caenis diminuta
Caenis diminuta
Caenis horaria
Caenis horaria
Caenis luctuosa
Caenis luctuosa
Caenis pseudorivulorum
Caenis pseudorivulorum
Caenis punctata
Caenis punctata
Caenis pycnacantha
Caenis pycnacantha
Caenis rivulorum
Caenis rivulorum
Caenis robusta
Caenis robusta
Caenis youngi
Caenis youngi
Choroterpes picteti
Choroterpes picteti
Cloeon bengalense
Cloeon bengalense
Cloeon fluviatile
Cloeon fluviatile
Cloeon harveyi
Cloeon harveyi
Cloeon paradieniensis
Cloeon paradieniensis
Cloeon viridulum
Cloeon viridulum
Drunella paradinasi
Drunella paradinasi
Ephemera formosana
Ephemera formosana
Ephemera japonica
Ephemera japonica
Ephemera pictipennis
Ephemera pictipennis
Ephemera rufomaculata
Ephemera rufomaculata
Ephemera zettana
Ephemera zettana
Ephoron capensis
Ephoron capensis
Ephoron nigridorsum
Ephoron nigridorsum
Ephoron savignyi
Ephoron savignyi
Ephoron shigae
Ephoron shigae
Ephoron virgo
Ephoron virgo
Eurylophella iberica
Eurylophella iberica
Homoeoneuria dolani
Homoeoneuria dolani
Homoeoneuria salviniae
Homoeoneuria salviniae
Isonychia diversa
Isonychia diversa
Isonychia formosana
Isonychia formosana
Isonychia fuscimarginata
Isonychia fuscimarginata
Isonychia hoffmani
Isonychia hoffmani
Isonychia ignota
Isonychia ignota
Isonychia japonica
Isonychia japonica
Isonychia latias
Isonychia latias
Isonychia moyarensis
Isonychia moyarensis
Isonychia sayi
Isonychia sayi
Isonychia vshivkovae
Isonychia vshivkovae
Leptohyphes sabinas
Leptohyphes sabinas
Leptohyphes zalope
Leptohyphes zalope
Metretopus alter
Metretopus alter
Neoephemera bicolor
Neoephemera bicolor
Neoephemera compressa
Neoephemera compressa
Neoephemera maxima
Neoephemera maxima
Pseudiron meridionalis
Pseudiron meridionalis
Serratella albai
Serratella albai
Serratella hispanica
Serratella hispanica
Siphlonurus aestivalis
Siphlonurus aestivalis
Siphlonurus binotatus
Siphlonurus binotatus
Siphlonurus davidi
Siphlonurus davidi
Siphlonurus flavidus
Siphlonurus flavidus
Siphlonurus hispanicus
Siphlonurus hispanicus
Siphlonurus lusoensis
Siphlonurus lusoensis
Siphlonurus orientalis
Siphlonurus orientalis
Siphlonurus palaearcticus
Siphlonurus palaearcticus
Siphlonurus yoshinoensis
Siphlonurus yoshinoensis
Siphloplecton brunneum
Siphloplecton brunneum
Siphloplecton costalense
Siphloplecton costalense
Siphloplecton fuscum
Siphloplecton fuscum
Siphloplecton speciosum
Siphloplecton speciosum
Thraulodes gonzalesi
Thraulodes gonzalesi
Tortopsis parishi
Tortopsis parishi
Tortopus harrisi
Tortopus harrisi
Tortopus primus
Tortopus primus
Traverella presidiana
Traverella presidiana
Tricorythodes albilineatus
Tricorythodes albilineatus
Tricorythodes fictus
Tricorythodes fictus
Tricorythodes stygiatus
Tricorythodes stygiatus
Acentrella feropagus
Acentrella feropagus