Carleton Wolsey Washburne, The World’s Good Education for World-Mindedness, New York,          J. Day, 1954.

When the larva of the caddis-fly, in the bottom of a brook, has laboriously built itself a tubelike protective case, another caddis larva will sometimes try to steal the case rather than build one of its own.
It enters the rear end of the tube and nips the tail end of the occupant. Sometimes the first one turns end for end quickly and meets the intruder jaw to jaw. Or sometimes it vacates promptly, goes quickly around to the rear end of the tube and nips the tail end the intruder to drive it out ; then the intruder may do the same thing, and so on until one gets tired of the battle.