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

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

Lateral view of a Psychodidae True Fly Larva from Mystery Creek #308 in Washington
This wild-looking little thing completely puzzled me. At first I was thinking beetle or month larva, until I got a look at the pictures on the computer screen. I made a couple of incorrect guesses before entomologist Greg Courtney pointed me in the right direction with Psychodidae. He suggested a possible genus of Thornburghiella, but could not rule out some other members of the tribe Pericomini.
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.

Light Cahill Spinners

Like most common names,"Light Cahill Spinner" can refer to more than one taxon. They're previewed below, along with 6 specimens. For more detail click through to the scientific names.

Mayfly Genus Stenacron

These are sometimes called Light Cahill Spinners.
The species in this genus were formerly classified in Stenonema. See the genus Maccaffertium for details. Only one species, Stenacron interpunctatum, is important to fly fishermen. See its page for details.
Artistic view of a Male Stenacron (Heptageniidae) (Light Cahill) Mayfly Dun from the Teal River in Wisconsin
Lateral view of a Male Stenacron interpunctatum (Heptageniidae) (Light Cahill) Mayfly Spinner from the Namekagon River in Wisconsin
Stenacron (Heptageniidae) (Light Cahill) Mayfly Nymph from unknown in Wisconsin

Mayfly Species Stenonema ithaca

These are sometimes called Light Cahill Spinners.
Lateral view of a Female Stenonema ithaca (Heptageniidae) (Light Cahill) Mayfly Dun from the Little Juniata River in Pennsylvania
This female looks very much like a male I collected a few hundred miles away a few days later, so I'm guessing it's the same species, which I believe is Maccaffertium mediopunctatum.
Lateral view of a Stenonema ithaca (Heptageniidae) (Light Cahill) Mayfly Nymph from Paradise Creek in Pennsylvania
This specimen seems to be of the same species as a dun I photographed which emerged from another nymph in the same sample.

Mayfly Species Cinygma dimicki

These are very rarely called Light Cahill Spinners.
Lateral view of a Male Cinygma dimicki (Heptageniidae) (Western Light Cahill) Mayfly Spinner from the Cedar River in Washington
I found a couple small (one or two dozen flies) clouds of these male spinners dancing low over the riffly parts of a pool in this fast river draining out of the Cascades.

Light Cahill Spinners

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