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 haven't keyed this specimen out, but I am instead placing it in Hydropsyche based on the striking visual similarity to this one, which I did key out.
This caddisfly was collected from the Madison River in Montana on June 30th, 2019 and added to Troutnut.com by Troutnut on July 17th, 2019.