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 Skwala nymph still has a couple months left to go before hatching, but it's still a good representative of its species, which was extremely abundant in my sample for a stonefly of this size. It's obvious why the Yakima is known for its Skwala hatch.
GONZO on Oct 28, 2008October 28th, 2008, 6:50 am EDT
This looks like Paragnetina to me, and the genital hooks (as best I can make out) seem to fit that ID. My resources for identifying adult Perlidae are pretty thin, so I welcome comments from others. (#707 looks like it might be another.)