This Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
Described by Hagen, H.A. (1861) Synopsis of the Neuroptera of North America. With a List of the South American Species. Smithsonian Miscellaneous Collections, 1–347.