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.
"Many men go fishing their entire lives without knowing it is not fish they are after." ~ Henry David Thoreau (1817-1862) American Essayist, Poet, Naturalist