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.

The "Fountain Flats" stretch of the Firehole was fishable in the morning after an uncharacteristically cold August night.

From the Firehole River in Wyoming

Stream photos

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Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva Glossosoma (Little Brown Short-horned Sedge) Caddisfly Larva

Dorsal view of a Glossosoma (Glossosomatidae) (Little Brown Short-horned Sedge) Caddisfly Larva from the Yakima River in Washington

I caught this tiny larva without a case, but it seems to key pretty clearly to to Glossosomatidae. From there, the lack of sclerites on the mesonotum points to either Glossosoma or Anagapetus. Although it's difficult to see in a 2D image from the microscope, it's pretty clear in the live 3D view that the pronotum is only excised about 1/3 of its length to accommodate the forecoxa, not 2/3, which points to Glossosoma at Couplet 5 of the Key to Genera of Glossosomatidae Larvae.

11 Recently Added Photos

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.

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Female Sweltsa (Sallfly) Stonefly Adult Pictures

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.

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

Ruler view of a Female Sweltsa (Chloroperlidae) (Sallfly) Stonefly Adult from the Madison River in Montana The smallest ruler marks are 1 mm.

Female Sweltsa (Chloroperlidae) (Sallfly) Stonefly Adult from the Madison River in Montana

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

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

This stonefly was collected from the Madison River in Montana on June 30th, 2019 and added to Troutnut.com by Troutnut on July 17th, 2019.

Discussions of this Adult

Sweltsa?

1 replies

Posted by Taxon on Jul 17, 2019

Last reply on Jul 17, 2019 by Troutnut

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.

Anyone able to ID this Chloroperlid?

Posted by Troutnut on Jul 17, 2019

Last reply on Jul 17, 2019 by Troutnut

I didn't do the best job taking pictures of key characteristics (such as wing venation), but I'm hoping somebody might be familiar with the striking color pattern. I'd love to know the species on this one.

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