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 Nelson, C.R. & Baumann, R.W. (1987) The winter stonefly genus Capnura (Plecoptera: Capniidae) in North America: systematics, phylogeny, and zoogeography. Transactions of the American Entomological Society 113, 1–28.