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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.

Lateral view of a Clostoeca disjuncta (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
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 Ameletus suffusus (Brown Dun) Mayfly Nymph Pictures

A few of these nymphs turned up in my kick net sample, with this being the only one fully mature and ready to emerge. It keys pretty straightforwardly to Ameletus suffusus, particularly because of the triangular dark patch on the labrum. The abdominal markings are close but don't quite match other drawings, likely just individual variation.

Dorsal view of a Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Ventral view of a Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Ruler view of a Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington The smallest ruler marks are 1 mm.
Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Closeup of the mouthparts with a box around the triangular shape on the labrum that identifies this species.

Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington
Closeup of the left gill from abdominal segment 5

Male Ameletus suffusus (Ameletidae) (Brown Dun) Mayfly Nymph from the Cedar River in Washington

This mayfly was collected from the Cedar River in Washington on July 2nd, 2021 and added to Troutnut.com by Troutnut on July 4th, 2021.


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Male Ameletus suffusus (Brown Dun) Mayfly Nymph Pictures

Collection details
Location: Cedar River, Washington
Date: July 2nd, 2021
Added to site: July 4th, 2021
Author: Troutnut
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