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. (1936) Some New Species of Stoneflies From Oregon (Plecoptera). Annals of the Entomological Society of America 29, 256–265, 2 pl.