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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Female Skwala (Large Springfly) Stonefly Adult Female Skwala (Large Springfly) Stonefly Adult

Lateral view of a Female Skwala (Perlodidae) (Large Springfly) Stonefly Adult from Mystery Creek #308 in Washington

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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.

Osobenus yakimae (Yakima Springfly) Stonefly Nymph Pictures

This nymph keys out to Osobenus yakimae, and a comparison of the markings with a specimen on flyfishingentomology.com provides a good verification. The size is about right, as that species has been described as 12 mm. The markings generally fit the original description of the nymph of that species (Jewett 1955) perfectly.

Dorsal view of a Osobenus yakimae (Perlodidae) (Yakima Springfly) Stonefly Nymph from the South Fork Snoqualmie River in Washington

Osobenus yakimae (Perlodidae) (Yakima Springfly) Stonefly Nymph from the South Fork Snoqualmie River in Washington

Ventral view of a Osobenus yakimae (Perlodidae) (Yakima Springfly) Stonefly Nymph from the South Fork Snoqualmie River in Washington

Ruler view of a Osobenus yakimae (Perlodidae) (Yakima Springfly) Stonefly Nymph from the South Fork Snoqualmie River in Washington The smallest ruler marks are 1 mm.

Lateral view of a Osobenus yakimae (Perlodidae) (Yakima Springfly) Stonefly Nymph from the South Fork Snoqualmie River in Washington

This stonefly was collected from the South Fork Snoqualmie River in Washington on June 13th, 2019 and added to Troutnut.com by Troutnut on June 14th, 2019.

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