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.
Grew up and live in North Western Montana. Been fly fishing for 28 years. Married with two boys. My wife fly fishes and so does my oldest son. I'm sure the young one will also. Consider myself a conservative conservationist. Mainly a trout fisherman. Very much a wild trout snob. Dry fly fanatic. 12' leaders and size 20 dry's.