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.
This peculiar midge lived in a case tightly fixed to a rock, with several others of its kind. The case seems to be made of tiny grains of sand. I'm not sure what the function is for the little lines sticking out the front, because they aren't legs.