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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Dorsal view of a Epeorus albertae (Heptageniidae) (Pink Lady) Mayfly Nymph from the East Fork Issaquah Creek in Washington
This specimen keys to the Epeorus albertae group of species. Of the five species in that group, the two known in Washington state are Epeorus albertae and Epeorus dulciana. Of the two, albertae has been collected in vastly more locations in Washington than dulciana, suggesting it is far more common. On that basis alone I'm tentatively putting this nymph in albertae, with the large caveat that there's no real information to rule out dulciana.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
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Mayfly Species Ephemerella alleni

Species Range

Physical description

Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.

Male Spinner

Body length: 9.5–10.2 mm
Wing length: 10.8 mm

Caudal filaments 12.7 mm. Head dark brown. Antennae with scape and pedicel dark brown; basal flagellar segments dark brown, distal segments pale. Ocelli white; base brown with proximal black ring. Compound eyes contiguous; upper portion orange-red; lower portion black. Thorax dark brown with variable pale and black markings; prothorax with median ridge. Wings hyaline with milky tinge; stigmatic area lightly clouded with white; costa and subcosta light brown; some longitudinal veins light brown distally, otherwise pale; intercalaries and crossveins hyaline. Forelegs brown to pale brown, each tarsal segment with pale distal ring; length (mm) of segments: trochanter = 0.4, femur =2.0, tibia=2.9, tarsus I =0.1, tarsus II = 1.0, tarsus Il = 1.1, tarsus IV = 1.0, tarsus V = 0.3. Midand hindlegs pale with brown distal tarsal segments and claws. Abdomen dark purple-brown anteriorly, red-brown posteriorly. Abdominal terga with pale anterior margin with paired, brown, submedian, saggital streaks, and with pair of pale sublateral spots ringed with brown. Abdominal pleura pale. Abdominal sterna pale, with brown triangles in anterolateral corners and paired submedial maculae; segments 1, 2, and 4-7 with ganglionic marks; sternum 9 brown laterally. Genitalia (fig. 1) brown with forceps pale medially. Penes with medioapical cleft and dorsal mediolongitudinal groove. Penes lobes with stout, spinulelike setae medially near outer margin, and with small, spinulelike setae along inner margin of cleft; with setal pits near outer margin in distal half, and with slightly developed apical projections. Forceps segment 2 slightly expanded distally; forceps segment 3 ovoid, with length nearly 1.5 X width. Median caudal filament and cerci subequal in length, purple-brown proximally, pale distally, with dark annulations at distal margin of each segment, and covered with hairlike setae.

Female Spinner

Body length: 10.2–10.7 mm
Wing length: 11.2–12.5 mm

Caudal filaments 12.1 mm. Head pink with dark brown triangle on occiput. Thorax with pink maculation; longitudinal wing veins brown. Abdominal segments 1-8 translucent; segments 1, 8—10 with extensive pink maculation; segments 6 and 7 with few pink maculations; terga 1-10 with posterior margins brown. Otherwise similar to male.

Start a Discussion of Ephemerella alleni


Mayfly Species Ephemerella alleni

Species Range
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