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.

Stream photos

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Setvena wahkeena (Wahkeena Springfly) Stonefly Nymph Setvena wahkeena (Wahkeena Springfly) Stonefly Nymph

Dorsal view of a Setvena wahkeena (Perlodidae) (Wahkeena Springfly) Stonefly Nymph from Mystery Creek #199 in Washington

As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.

7 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.

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.

Quick bug stop on the Dosewallips River

By Troutnut on July 5th, 2020

This long day trip from home to the Olympic Peninsula was primarily an attempt to dig a geoduck, a Pacific Northwest delicacy and the largest species of burrowing clam. I built a special tool to help dig them up from 3 feet under the sediment in the tidal flat off the Dosewallips River estuary, where the big clams are exposed only during the lowest tides of the summer. They're apparently located among the eelgrass at this beach by locating where they spurt jets of water 5-10 feet into the air as the tide recedes or rises. Unfortunately, I didn't see a single jet of water nor any other sign of a geoduck, even with the tide dropping to -2.8 feet.

My consolation prizes were some delicious steamer clams (manila clams), an easy find higher in the tidal zone, and some bugs to photograph from a short sampling stop upriver.

Photos by Troutnut

Closeup insects by Troutnut from the Dosewallips River in Washington

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Brachycentrus americanus (American Grannom) Caddisfly Larva

Case view of a Brachycentrus americanus (Brachycentridae) (American Grannom) Caddisfly Larva from the Dosewallips River in Washington

Both the genus ID (Merritt & Cummins) and species ID (Flint 1984) are pretty confident for this larva, a nice example of a common western caddisfly. It was by far the most abundant insect in my kicknet sample on this trip, and many of the rocks in the fast riffle where I sampled had dozens of these larvae clinging on.

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Drunella grandis (Western Green Drake) Mayfly Nymph

Lateral view of a Drunella grandis (Ephemerellidae) (Western Green Drake) Mayfly Nymph from the Dosewallips River in Washington

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Male Baetis flavistriga (BWO) Mayfly Nymph

Dorsal view of a Male Baetis flavistriga (Baetidae) (BWO) Mayfly Nymph from the Dosewallips River in Washington

This nymph keys to Baetis assuming the villipore is present (hard to see in my photos or scope), and within that genus it tentatively keys to the flavistriga species complex, of which Baetis flavistriga itself is by far the most common in Washington state, so that's the most likely ID.

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Ephemerella excrucians (Pale Morning Dun) Mayfly Nymph

Dorsal view of a Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Nymph from the Dosewallips River in Washington

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Neoleptophlebia memorialis Mayfly Nymph

Artistic view of a Neoleptophlebia memorialis (Leptophlebiidae) Mayfly Nymph from the Dosewallips River in Washington

This specimen keys to the Neoleptophlebia memorialis group, which means it could be Neoleptophlebia memorialis or Neoleptophlebia temporalis. In the absence of a clear species key, I'm just guessing memorialis for now.

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Epeorus longimanus (Slate Brown Dun) Mayfly Nymph

Dorsal view of a Epeorus longimanus (Heptageniidae) (Slate Brown Dun) Mayfly Nymph from the Dosewallips River in Washington

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Cinygmula (Dark Red Quill) Mayfly Nymph

Dorsal view of a Cinygmula (Heptageniidae) (Dark Red Quill) Mayfly Nymph from the Dosewallips River in Washington

Unfortunately there's no good key to species of Cinygmula nymphs and I didn't find an adult, so this one will have to stay at genus level.

Comments / replies

Wbranch

York & Starlight PA

Posts: 2635

Wbranch on Jul 16, 2020July 16th, 2020, 1:38 am EDT

Wow, what a great looking pool! You should of fished there awhile.

Catskill fly fisher for fifty-five years.

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Jul 16, 2020July 16th, 2020, 5:44 pm EDT

I had brought fly fishing gear, but we had to get back. This part of the Olympic Peninsula doesn't have much resident trout fishing, as far as I know. It's almost completely a sea-run fishery and the run wasn't in yet.

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist