Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
Featured on the forum
Nymphs of this species were fairly common in late-winter kick net samples from the upper Yakima River. Although I could not find a key to species of Zapada nymphs, a revision of the Nemouridae family by Baumann (1975) includes the following helpful sentence: "2 cervical gills on each side of midline, 1 arising inside and 1 outside of lateral cervical sclerites, usually single and elongate, sometimes constricted but with 3 or 4 branches arising beyond gill base in Zapada cinctipes." This specimen clearly has the branches and is within the range of that species.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and
fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or
support the project for an enhanced experience here.
Pale Sulphur Duns
Like most common names,"Pale Sulphur Dun" can refer to more than one taxon. They're previewed below, along with 10 specimens. For more detail click through to the scientific names.
Mayfly Species Stenonema ithaca
These are sometimes called Pale Sulphur Duns.
This female looks very much like a male I collected a few hundred miles away a few days later, so I'm guessing it's the same species, which I believe is Maccaffertium mediopunctatum.
This specimen seems to be of the same species as a dun I photographed which emerged from another nymph in the same sample.
See 2 more specimens...
Mayfly Species Ephemerella dorothea dorothea
These are very rarely called Pale Sulphur 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.
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.
I keyed this nymph carefully under a microscope to check that it's Ephemerella dorothea.
Mayfly Species Ephemera varia
These are very rarely called Pale Sulphur Duns.
This is an excellent hatch of a different character than its Ephemera brethren. Rather than emerging in a flurry of activity within a week, the Ephemera varia hatch may last for more than a month in a single place.
This yellow drake dun hatched out of my aquarium over a month before her brethren in the wild are slated to emerge. She seems a bit small, and that might be the reason.
I found this female spinner ovipositing in a small stream. She came along while I was playing a trout -- every good bug seemed to do that last night! I didn't have my bug net, so I caught the trout in my landing net, released the trout, and caught the mayfly in my landing net. Her wing got a bit messed up from that.
Mayfly Species Epeorus vitreus
These are very rarely called Pale Sulphur 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.
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.
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.
See 12 more specimens...
References
- Baumann, Richard W. 1975. Revision of the Stonefly Family Nemouridae (plecoptera) : a Study Of The World Fauna At The Generic Level. Smithsonian Contributions to Zoology undef(211): 1-74.