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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.

Dorsal view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
This specimen appears to be of the same species as this one collected in the same spot two months earlier. The identification of both is tentative. This one suffered some physical damage before being photographed, too, so the colors aren't totally natural. I was mostly photographing it to test out some new camera setting idea, which worked really well for a couple of closeups.
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.

Female Caudatella heterocaudata Mayfly Dun Pictures

These duns were emerging sporadically throughout a cloudy evening at the end of June. Had I looked more closely when I caught this one and realized it represented my first collection of this genus, or just noticed the really striking coloration, I would have set my fly rod on shore and spent more time lurking mid-river with my net trying to catch more of them emerging (and at least one in better shape).

It's always a bit difficult to identify a female dun, but in this case the three longitudinal stripes on the sternites are very distinctive and narrow the choices to Caudatella heterocaudata and Caudatella columbiella. However, the length of the fore wing measured with a caliper is 7.25 mm, whereas columbiella should be no more than 6 mm, so heterocaudata appears to be the correct ID.

Lateral view of a Female Caudatella heterocaudata (Ephemerellidae) Mayfly Dun from the Cedar River in Washington
Dorsal view of a Female Caudatella heterocaudata (Ephemerellidae) Mayfly Dun from the Cedar River in Washington
Ventral view of a Female Caudatella heterocaudata (Ephemerellidae) Mayfly Dun from the Cedar River in Washington
Ruler view of a Female Caudatella heterocaudata (Ephemerellidae) Mayfly Dun from the Cedar River in Washington The smallest ruler marks are 1 mm.

This mayfly was collected from the Cedar River in Washington on June 30th, 2021 and added to Troutnut.com by Troutnut on July 2nd, 2021.


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Female Caudatella heterocaudata Mayfly Dun Pictures

Collection details
Location: Cedar River, Washington
Date: June 30th, 2021
Added to site: July 2nd, 2021
Author: Troutnut
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