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.
Described by Kirchner, R.F. & Kondratieff, B.C. (1984) A new Diploperla from West Virginia (Plecoptera: Perlodidae). Proceedings of the Entomological Society of Washington 86, 648–652.