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Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana
Salmonflies
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 Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington
As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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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Pale Evening Duns

Anglers usually shorten the Pale Evening Dun hatch to the PED hatch.


Like most common names,"Pale Evening Dun" can refer to more than one taxon. They're previewed below, along with 12 specimens. For more detail click through to the scientific names.

Mayfly Species Ephemerella dorothea dorothea

These are pretty much always called Pale Evening Duns.
Ephemerella dorothea consists of two subspecies, which both produce excellent action. Ephemerella dorothea dorothea is a small species of Sulphur in the East, and Ephemerella dorothea infrequens (formerly Ephemerella infrequens) is one of the two main Pale Morning Dun hatches of the West. The remainder of this page focuses on the dorothea dorothea subspecies, and Ephemerella dorothea infrequens is discussed separately on its own page.

This is one of the most challenging mayfly hatches on Eastern waters. On many streams, it follows or overlaps hatches of the larger, lingering Ephemerella invaria.
Dorsal view of a Ephemerella dorothea dorothea (Ephemerellidae) (Pale Evening Dun) Mayfly Nymph from Paradise Creek in Pennsylvania
I keyed this nymph carefully under a microscope to check that it's Ephemerella dorothea.

Mayfly Species Heptagenia elegantula

These are often called Pale Evening Duns.
The spinner falls of this elegant species can be quite important to anglers across the West. Recent revisions have synonymized the Midwestern species Heptagenia diabasia that may be of some local importance.

Mayfly Species Ephemerella invaria

These are often called Pale Evening Duns.
This species, the primary "Sulphur" hatch, stirs many feelings in the angler. There is nostalgia for days when everything clicked and large, selective trout were brought to hand. There is the bewildering memory of towering clouds of spinners which promise great fishing and then vanish back into the aspens as night falls. There is frustration from the maddening selectivity with which trout approach the emerging duns--a vexing challenge that, for some of us, is the source of our excitement when Sulphur time rolls around.

Ephemerella invaria is one of the two species frequently known as Sulphurs (the other is Ephemerella dorothea). There used to be a third, Ephemerella rotunda, but entomologists recently discovered that invaria and rotunda are a single species with an incredible range of individual variation. This variation and the similarity to the also variable dorothea make telling them apart exceptionally tricky.

As the combination of two already prolific species, this has become the most abundant of all mayfly species in Eastern and Midwestern trout streams.
Lateral view of a Male Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Dun from Penn's Creek in Pennsylvania
Lateral view of a Male Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Spinner from the Teal River in Wisconsin
Dorsal view of a Ephemerella invaria (Ephemerellidae) (Sulphur) Mayfly Nymph from the Beaverkill River in New York
This small Ephemerella invaria nymph was at least a month away from emergence.

Mayfly Species Leucrocuta aphrodite

These are sometimes called Pale Evening Duns.
This is one of the few Eastern species of the Heptagenia complex to produce fishable hatches.

Mayfly Species Leucrocuta hebe

These are sometimes called Pale Evening Duns.
This widespread species produces more fishable hatches in the East and Midwest than any other species in the Heptagenia genus complex.
Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Dun from the Beaverkill River in New York
I found Catskill brown trout eagerly surface feeding to this species.
Lateral view of a Female Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Spinner from Mystery Creek #43 in New York
I found this spinner on the same piece of stream as a similar dun, probably of the same species.
Dorsal view of a Leucrocuta hebe (Heptageniidae) (Little Yellow Quill) Mayfly Nymph from the Bois Brule River in Wisconsin

Mayfly Species Epeorus vitreus

These are sometimes called Pale Evening Duns.
This is the second most common Epeorus species in the East and Midwest. Most anglers will encounter sporadic hatches of Epeorus vitreus once in a while, and sometimes a more concentrated emergence causes a good rise of fish.
Male Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Dun from the Beaverkill River in New York
This is my favorite mayfly from 2004, and it appears on my popular Be the Trout: Eat Mayflies products. Check them out!

Its identification is really up in the air. It might be a late-season vitreus dun but it may very well be one of the more obscure species in that genus.
Artistic view of a Female Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Spinner from the Namekagon River in Wisconsin
Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Nymph from unknown in Wisconsin
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