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.

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Sweltsa?

Female Sweltsa (Sallfly) Stonefly Adult

8 Pictures

Lateral view of a Female Sweltsa (Chloroperlidae) (Sallfly) Stonefly Adult from the Madison River in Montana

These stoneflies--abundant during midday--seemed at first to be flying around with plain yellow bodies, but on closer inspection turn out to have striking, fiery red abdomens.

Collected June 29, 2019 from the Madison River in Montana

Added by Troutnut on July 17, 2019

Collected June 29, 2019 from the Madison River in Montana and added by Troutnut on July 17, 2019

Taxon

Site Editor
Plano, TX

Posts: 1311

Taxon on Jul 17, 2019July 17th, 2019

Hi Jason-

My guess would be genus Sweltsa, of which I believe there to be ~8 species in MT. It looks pretty similar to a (mostly) dorsal view of Sweltsa townsesi, which is pictured in American Stoneflies: A Photographic Guide to the Plecoptera by Bill B. Stark, et. al. However, I believe that species is only present in the Northern Sierra Nevada Mountains of CA and NV.

Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com

Troutnut

Administrator
Bellevue, WA

Posts: 2758

Troutnut on Jul 17, 2019July 17th, 2019, 8:03 pm EDT

Thanks Roger. I'll put it there for now, along with another specimen of similar but not identical coloration and a few mm greater length.

FYI, today and tomorrow I'm adding quite a few more specimens from this year's Montana trip and would definitely appreciate any ID thoughts if you have time. I'll message Dave about the caddis soon, too.

Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist

SalmonfliesPteronarcys californica

Troutnut Forum › Specimen Discussion › Sweltsa?