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 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.
Described by Stark, B.P. & Stewart, K.W. (1983) New records and descriptions of Alloperla (Plecoptera: Chloroperlidae) from the Ozark-Ouachita region. Entomological News 94, 55–59.