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 Baumann, R.W. & Gaufin, A.R. (1970) The Capnia projecta complex of western North America (Plecoptera: Capniidae). Transactions of the American Entomological Society 96, 435–468.