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.

Mayfly Dun to Spinner Illustrated

Most fly anglers know that mayflies have two adult stages: duns and spinners. Entomologists call them subimagos and imagos. See the main Ephemeroptera page for the basics of these two stages.

Much of angling literature and this website consists of tips about matching one stage or the other for the various species. In May of 2005 I caught one mayfly molting between the two stages.

It belongs to the species Leptophlebia cupida, which anglers know as the Black Quill.

The Dun

The Molting Process

The skin of the dun splits above the thorax and it anchors its tarsi to the surface it's resting on. The entire spinner wriggles out forward through the opening in the thorax.

The Spinner

Readers who enjoy this sequence will also enjoy the shots of an Ephemera varia dun molting into a spinner in Ted Fauceglia's book Mayflies . His photos present the same process in a much more artistic manner.