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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 Female Sweltsa borealis (Chloroperlidae) (Boreal Sallfly) Stonefly Adult from Harris Creek in Washington
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
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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Teloganopsis deficiens (Little Black Quill) Mayfly Nymph Pictures

This nymph has tiny, barely detectable tubercles on its abdominal segments, and I could not find the maxillary palpi. I tentatively guessed that it is Serratella deficiens back when that was a thing; the species is now known as Teloganopsis deficiens. One of the key characteristics, tarsal claws with a subapical denticle being larger than the preceding denticles, seems to be visible in some of the pictures.

Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin
Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin
Dorsal view of a Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin
Ventral view of a Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin
Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin
Teloganopsis deficiens (Ephemerellidae) (Little Black Quill) Mayfly Nymph from the Bois Brule River in Wisconsin

This mayfly was collected from the Bois Brule River in Wisconsin on June 9th, 2005 and added to Troutnut.com by Troutnut on May 26th, 2006.


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Teloganopsis deficiens (Little Black Quill) Mayfly Nymph Pictures

Collection details
Location: Bois Brule River, Wisconsin
Date: June 9th, 2005
Added to site: May 26th, 2006
Author: Troutnut
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