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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 Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington
This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.
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 Cinygmula uniformis Mayfly Spinner Pictures

The identification of this specimen is not positive because some of the key characteristics conflict. The uniform amber tint of the wings and the rusty-colored mid-ventral markings on some of the abdominal sternites point to Cinygmula uniformis, but I could not locate the small ventral subapical spines on the penes that are supposed to also diagnose that species (the ones visible in the pictures aren't the ones I'm talking about). If I prioritize that characteristics, this would probably be Cinygmula mimus, but then the wing and sternite shading/markings are wrong.

Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Lateral view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Ruler view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.
Dorsal view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Ventral view of a Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington
Male Cinygmula uniformis (Heptageniidae) Mayfly Spinner from the South Fork Snoqualmie River in Washington

This mayfly was collected from the South Fork Snoqualmie River in Washington on May 22nd, 2022 and added to Troutnut.com by Troutnut on May 24th, 2022.


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Male Cinygmula uniformis Mayfly Spinner Pictures

Collection details
Location: South Fork Snoqualmie River, Washington
Date: May 22nd, 2022
Added to site: May 24th, 2022
Author: Troutnut
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