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.
After camping atop the Gravelly Range and mostly dodging thunderstorms throughout the day, we set up to camp in the evening at Cottonwood Campground along the upper Ruby and drove to fish a nearby reach that looked good on Google Earth. There wasn't much visible bug activity and I didn't see a single fish, but I did manage to find five small to medium rainbows on nymphs and soft-hackles.