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 Frison, T.H. (1942) Descriptions, Records and Systematic Notes Concerning Western North American Stoneflies (Plecoptera). The Pan-Pacific Entomologist 18, 9–16.