Artistic view of a Male Pteronarcys californica (Pteronarcyidae) (Giant Salmonfly) Stonefly Adult from the Gallatin River in Montana

Salmonflies
Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

Stream photos

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Female Sweltsa borealis (Boreal Sallfly) Stonefly Adult Female Sweltsa borealis (Boreal Sallfly) Stonefly Adult

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.

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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.

Isonychia bicolor (Mahogany Dun) Mayfly Nymph Pictures

This Isonychia bicolor nymph from the Catskills displays the prominent white stripe sometimes characteristic of its species. This is the first such specimen I've photographed, because members of the same species in the Upper Midwest have a more subdued stripe (and were once thought to be a different species, Isonychia sadleri). The striking coloration on this eastern nymph is more appealing.

Artistic view of a Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Nymph from the Beaverkill River in New York

Dorsal view of a Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Nymph from the Beaverkill River in New York

Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Nymph from the Beaverkill River in New York

This species does not behave well for the camera, so I eventually killed this specimen in alcohol to get a better picture of the mouth parts. This resulting unnatural pose shows them well.

Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Nymph from the Beaverkill River in New York

This mayfly was collected from the Beaverkill River in New York on April 19th, 2006 and added to Troutnut.com by Troutnut on April 21st, 2006.

Discussions of this Nymph

Sare

Posted by Sare on Jan 28, 2020

Last reply on Jan 28, 2020 by Sare

I just love your webpage and all the info you guys provide and the pics are incredible.
Please keep up the great work you are doing - no other webpage comes close to you guys.
Thanks Sare

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