The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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.
Millcreek on Jul 22, 2015July 22nd, 2015, 6:56 pm EDT
John -
I'm still not sure although if I had to guess it would be Doroneuria.
This may help. It's a guy who does mostly eastern bugs but occasionally does some western critters.