Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

Stream photos

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Tricorythodes (Trico) Mayfly Nymph Tricorythodes (Trico) Mayfly Nymph

Dorsal view of a Tricorythodes (Leptohyphidae) (Trico) Mayfly Nymph from Mystery Creek #308 in Washington

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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.

Glossosoma intermedium or nigrior

This topic is about the Caddisfly Genus Glossosoma

The sporadic emergence of these caddisflies diminishes the importance of the freshly emerged adults and pupae, but they have unique periods of vulnerability as larvae during the day and again as diving egg layers at dusk that can make them very important. A taxon can only have one common name attached in the title but this is one of those genera whose species come in a variety of colors and descriptive common names. In the West their bodies generally come in tan to brown shades with matching wings, their wings can be speckled grayish tan or even almost black as with an eastern species. Some western rivers have astounding populations. See Glossosomatidae for more information.

Example specimens

Wisconsin

Posts: 622

Wiflyfisher on Jun 30, 2020June 30th, 2020, 11:45 am EDT

Caught and photographed in the Upper Midwest on May 12, 2020. I resized my original photo for the website.

John S.
https://WiFlyFisher.com

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Jul 1, 2020July 1st, 2020, 4:53 am EDT

Nice photo John!

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist

Wiflyfisher

Wisconsin

Posts: 622

Wiflyfisher on Jul 1, 2020July 1st, 2020, 7:20 am EDT

Jason, thanks.

I sent my two best original macro photos to an entomologist friend who believes they are Glossosoma intermedium or nigrior, which are common here.

I bet you can guess the river too, :-)

I hope all is well with you and your family. BTW, I still email back and forth with Frank P. and the new fishery manager quite often.

Stay safe!

John S.
https://WiFlyFisher.com

Creno
Grants Pass, OR

Posts: 302

Creno on Jul 18, 2020July 18th, 2020, 10:43 am EDT

Did you keep this specimen? The palps and antennae look too robust to be Glossosoma. How about one of the brachycentrids?

Wiflyfisher

Wisconsin

Posts: 622

Wiflyfisher on Jul 20, 2020July 20th, 2020, 12:49 pm EDT

Did you keep this specimen? The palps and antennae look too robust to be Glossosoma. How about one of the brachycentrids?

Yes, I have the specimen or another one in a specimen bottle with 90% iso alcohol.

I emailed my original photo to a professor in Michigan. He has made a study of all the caddisflies in the Upper Midwest. He "guessed" by looking at my full size photo that it was Glossosoma, which are common in northern Wisconsin. I could send him my specimen but I never got around to it.

John S.
https://WiFlyFisher.com

Creno
Grants Pass, OR

Posts: 302

Creno on Jul 31, 2020July 31st, 2020, 5:23 am EDT

I talked to Dave - send it to him, he is happy to look at it for you, and me :-)