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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.

Case view of a Pycnopsyche guttifera (Limnephilidae) (Great Autumn Brown Sedge) Caddisfly Larva from the Yakima River in Washington
It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.

I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.

The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.

Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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.


Posts: 37
BGrnFlyfish on Feb 18, 2008February 18th, 2008, 1:04 pm EST
To anyone out there; the Serendipity-kinda of a dumb question but i've been told a dumb question is a question unasked. What does this imitate and what colors do you recommend? Red, Green, Tan?
Seth-Big Green River, WI
Troutnut's profile picture
Bellevue, WA

Posts: 2758
Troutnut on Feb 18, 2008February 18th, 2008, 4:05 pm EST
I haven't used that pattern so I'm not very familiar with it, but based on googling it, it seems to be intended to imitate a caddis pupa, or sometimes a midge pupa. Therefore the colors and size that work best would depend on what's hatching at the time. I would guess olive is a good overall bet.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
CaseyP's profile picture
Arlington, VA/ Mercersburg, PA

Posts: 653
CaseyP on Feb 19, 2008February 19th, 2008, 3:51 am EST
the one day i used it, it was red, maybe 18 or 20, and worked a treat. it was April on the Little J.
"You can observe a lot by watching." Yogi Berra

Posts: 37
BGrnFlyfish on Feb 19, 2008February 19th, 2008, 4:12 am EST
Thanks guys!
Seth-Big Green River, WI
Potter County, PA

Posts: 144
SlateDrake9 on Feb 23, 2008February 23rd, 2008, 2:54 pm EST
I've never seen one that wasn't an olive brown color.

I always assumed they were midge pattern, but I guess they could be a small caddis. I've only fished them in 18-22 sizes.
Fishing with bait is like swearing in church.
-- Slate Drake

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