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.
Described by Walker, F. (1852) 1 Catalogue of the specimens of neuropterous insects in the collection of the British MuseumPart I. Phryganides-Perlides. Edward Newman, London. Available from: http://www.archive.org/details/catalogueofspeci00britrich 1-192