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 Nebeker, A.V. & Gaufin, A.R. (1965) The Capnia columbiana complex of North America (Capniidae: Plecoptera). Transactions of the American Entomological Society 91, 467–487.