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.
P.S. Didn't see any the last two nights, or much of anything hatching for that matter. Friday night I pulled out the old secret weapon, a #12 Royal Wulff, and a 15-incher fell for it.