Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
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.
Compound eye: The eyes of many arthropods, including insects and crustaceans, are composed of anywhere from 12 to 1,000 facets called ommatidia. These are called compound eyes.
This other word references the same concept: compound eyes.