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.

I caught a nice brookie a few weeks earlier in this pool at the junction of a split channel in the stream. The huge fallen tree is great cover.

From the Mystery Creek # 23 in New York

Stream photos

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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Lateral view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Yakima River in Washington

This specimen keys pretty easily to Onocosmoecus, and it closely resembles a specimen from Alaska which caddis expert Dave Ruiter recognized as this genus. As with that specimen, the only species in the genus documented in this area is Onocosmoecus unicolor, but Dave suggested for that specimen that there might be multiple not-yet-distinguished species under the unicolor umbrella and it would be best to stick with the genus-level ID. I'm doing the same for this one.

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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.

Insects from the Chena River

By Troutnut on May 9th, 2008

Back before I started my first real field season as a graduate student working on Chinook salmon in the Chena River, I took a fun personal trip up to the North Fork just after ice-out (yes, the ice breaks up that late here!) to collect some Alaskan insects to photograph for the site.

Closeup insects by Troutnut from the Chena River in Alaska

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Culicidae (Mosquito) True Fly Pupa

Lateral view of a Culicidae (Mosquito) True Fly Pupa from the Chena River in Alaska

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Female Copepoda (Copepod) Arthropod Adult

Dorsal view of a Female Copepoda (Copepod) Arthropod Adult from the Chena River in Alaska

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Copepoda (Copepod) Arthropod Adult

Lateral view of a Copepoda (Copepod) Arthropod Adult from the Chena River in Alaska

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Onocosmoecus (Great Late-Summer Sedge) Caddisfly Larva

Case view of a Onocosmoecus (Limnephilidae) (Great Late-Summer Sedge) Caddisfly Larva from the Chena River in Alaska

See the forum discussion for discussion with a caddis expert (Dave Ruiter / Creno) about the identification of this specimen. I'm a bit perplexed because some gills seem to have more than 4 branches, which would lead in a different direction at Couplet 18 of the Key to Genera of Limnephilidae Larvae, but Dave knew his stuff a lot better than I did. He was convinced this is Onocosmoecus. The current range maps would put this in Onocosmoecus unicolor as the only option, but he believed there are probably multiple not-yet-distinguished species under that umbrella and suggested keeping this one's ID at the genus level for that reason.

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Tipulidae (Crane Fly) True Fly Larva

Dorsal view of a Tipulidae (Crane Fly) True Fly Larva from the Chena River in Alaska

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Ephemerella aurivillii Mayfly Nymph

Dorsal view of a Ephemerella aurivillii (Ephemerellidae) Mayfly Nymph from the Chena River in Alaska

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Ephemerella aurivillii Mayfly Nymph

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Cinygmula (Dark Red Quill) Mayfly Nymph

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

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Chironomidae (Midge) True Fly Larva

Lateral view of a Chironomidae (Midge) True Fly Larva from the Chena River in Alaska

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Chloroperlidae (Sallfly) Stonefly Nymph

Dorsal view of a Chloroperlidae (Sallfly) Stonefly Nymph from the Chena River in Alaska

Comments / replies

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Apr 26, 2011April 26th, 2011, 5:28 pm EDT

Anyone want to help ID these bugs? I haven't had time to take a close look at them or run through any keys, but I'm sure some of you will know a more specific classification for some of these.

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist