Header image
Enter a name
Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
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.

Lateral view of a Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
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.
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.

Male Epeorus vitreus (Sulphur) Mayfly Dun Pictures

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.

Ruler view of a Male Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Dun from the Beaverkill River in New York The smallest ruler marks are 1/16".
Male Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Dun from the Beaverkill River in New York
Male Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Dun from the Beaverkill River in New York
Male Epeorus vitreus (Heptageniidae) (Sulphur) Mayfly Dun from the Beaverkill River in New York

This mayfly was collected from the Beaverkill River in New York on September 2nd, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.

Discussions of this Dun

Thoughts on this Heptageniid's ID?
1 replies
Posted by Troutnut on Jul 2, 2006
Last reply on Oct 28, 2008 by GONZO
This is one of my favorite specimens from the old site pictures. I collected it in early September during a fishable hatch of its kind on a smooth, deep pool on the Beaverkill.

The eyes seem nearly contiguous, the first two segments of the fore tarsi are of equal length, and the wings are unmarked, all of which suggest Epeorus. From the above/side picture I can see that the basal costal crossveins do not slant upward as they should with Epeorus, although the main side view seems to maybe show that. I wish I had a better camera when I photographed this one.

It also pretty strongly resembles the E. vitreus dun shown in Ted Fauceglia's book, Mayflies. It clearly does not match the E. vitreus dun pictured on Color Plate XII of Hatches II, but it looks like the unidentifeid eastern Epeorus species on Color Plate XIII of the same book.

By some accounts, there does not seem to be a common eastern species of Epeorus hatching this late, but other books show it on the tail end of the emergence times for Epeorus vitreus. So that's my best guess for now.

Start a Discussion of Dun

Male Epeorus vitreus (Sulphur) Mayfly Dun Pictures

Collection details
Location: Beaverkill River, New York
Date: September 2nd, 2004
Added to site: January 25th, 2006
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy