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.

The trees were leafing out and the trout were rising on this productive Wisconsin stream

From the Namekagon River in Wisconsin

Stream photos

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Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva

Dorsal view of a Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Larva from the Yakima River in Washington

I caught this tiny larva without a case, but it seems to key pretty clearly to to Glossosomatidae. From there, the lack of sclerites on the mesonotum points to either Glossosoma or Anagapetus. Although it's difficult to see in a 2D image from the microscope, it's pretty clear in the live 3D view that the pronotum is only excised about 1/3 of its length to accommodate the forecoxa, not 2/3, which points to Glossosoma at Couplet 5 of the Key to Genera of Glossosomatidae Larvae.

11 Recently Added Photos

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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Male Ephemerella excrucians (Pale Morning Dun) Mayfly Dun Pictures

Male Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho

Dorsal view of a Male Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho

Ventral view of a Male Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho

Ruler view of a Male Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho The smallest ruler marks are 1 mm.

Lateral view of a Male Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Dun from the Henry's Fork of the Snake River in Idaho

This mayfly was collected from the Henry's Fork of the Snake River in Idaho on July 31st, 2020 and added to Troutnut.com by Troutnut on August 17th, 2020.

Discussions of this Dun

Ventral view

1 replies

Posted by Martinlf on Sep 5, 2020

Last reply on Sep 6, 2020 by Troutnut

Love the ventral photo. One guide ties duns with green abdomens and a bit of orange in the thorax. I see why now. Super photos.

Public service announcement: PMDs aren't yellow

13 replies

Posted by Troutnut on Aug 17, 2020

Last reply on Aug 28, 2020 by Wiflyfisher

It seems like most of the imitations I see in fly shops for PMDs, and dubbing mixes or other body materials designed to imitate PMDs, are a pale yellow color. I would just like to use this specimen to point out that in many cases (or in all the cases I've seen), most true PMDs (Ephemerella excrucians) are not yellow, but olive (with a bit of a gold tinge). I have some RenÃ© Harrop PMD dubbing with the appropriate olive cast, but other than that I'm just seeing a lot of pale yellow more suited to eastern sulphur mayflies than excrucians.

The label PMD also applies to Ephemerella dorothea infrequens, but it seems they're also green as duns, unless I misidentified that specimen by associating an excrucians dun with nearby dorothea spinners.

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