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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.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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.

Updates from April 23, 2004

Updates from April 23, 2004

Photos by Troutnut

This muskrat swam around me for a while as I fished a caddisfly hatch.

Underwater photos by Troutnut

There's a very well-camouflaged Baetisca laurentina mayfly nymph resting on the twig in the bottom left corner of this picture. Can you spot him?
This is a pretty clear photo of an Epeorus nymph clinging flat against a log. The big mound of debris on the bottom center of the picture, attached to the light rock, is a structure that's been puzzling me. I've found several in one section of the river. It's big, like 2 inches long and maybe 1/2-3/4 inch wide/tall, and hollow, like some sort of coccoon or something. It's clearly a structure built by some sort of little creature, but I'm not sure what.
I'm not quite sure what this is.  It may be an Isonychia nymph hiding under a piece of grass.

Closeup insects by Troutnut from the Namekagon River in Wisconsin

Lateral view of a Male Siphloplecton basale (Metretopodidae) (Pseudo-Gray Drake) Mayfly Dun from the Namekagon River in Wisconsin
This one hatched on the same April Saturday that I saw the first Hendricksons of the season.
The wings aren't really yellowish; that's just the color they take on when they've been injured.

Male Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Dun from the Namekagon River in Wisconsin
Female Ephemerella subvaria (Ephemerellidae) (Hendrickson) Mayfly Dun from the Namekagon River in Wisconsin

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