This one pretty clearly keys to Kogotus, but it also looks fairly different from specimens I caught in the same creek about a month later in the year. With only one species of the genus known in Washington, I'm not sure about the answer to this ID.
Described by Kondratieff, B.C. & Baumann, R.W. (1999) Studies on stoneflies of North Dakota with the description of a new Perlesta species (Plecoptera: Perlidae). Proceedings of the Entomological Society of Washington 101, 325–331.