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.
During late summer & autumn large numbers of crane flies begin to hatch and loose the battle against the elements and end their life on the water as trout food. This daddy long legs pattern has quick & easy detached deer hair body technique that gives it a nice semi-realistic appearance.