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 have been told this is the only western aquatic moth, Petrophila confusalis, see here on milkweed blossoms.
This insect was collected from the Flathead River-lower in Montana on July 21st, 2005 and added to Troutnut.com by Bnewell on June 28th, 2011.