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.
To emerge, the adult, still in its pupal skin, cuts out of the case or shelter using special mandibles. It then rapidly swims to the surface of the water or the bank, using fringed legs. It is assisted in reaching the surface by a bubble of gas secreted between the adult and the skin. This however makes them appear as a silvery bubble that is very conspicuous to fish.