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 Needham, J.G. & Claassen, P.W. (1925) A Monograph of the Plecoptera or Stoneflies of America North of Mexico. The Thomas Say Foundation II, 1–397.