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.
I was not fishing, but happened to be at an unrelated social event on a hill above this tiny creek (which I never even saw) when this stonefly flew by me. I assume it came from there. Some key characteristics are tricky to follow, but process of elimination ultimately led me to Sweltsa borealis. It is reassuringly similar to this specimen posted by Bob Newell years ago. It is also so strikingly similar to this nymph from the same river system that I'm comfortable identifying that nymph from this adult. I was especially pleased with the closeup photo of four mites parasitizing this one.
Mesonotal setal areas: Setae on the mesonotum of caddisfly larvae arise mostly from three primary locations, denoted sa1, sa2, and sa3. These differ from the more commonly-referenced metanotal setal areas in that they do not necessarily appear on raised bumps. Often, the entire mesonotum is sclerotized, and these areas do not appear different from the rest of it except for the presence of the setae.
These other words reference the same concept: mesonotal setal area, mesonotal sa1, mesonotal sa2, mesonotal sa3.
