Arthur Koestler, The act of creation, Londres, Hutchinson, 1964, p. 486.

Equally surprising is the ingenuity of the caddis-fly larva. If a group of larvae are ejected from the tubular « houses » which they built, and are then allowed to return they often get mixed up and enter the wrong « house » which is either too big or too small. The larva then sets about to cut off parts of the tube or to add to it, until it fits it exactly. Again the ‘consummatory acts’ in these activities are quite from those in normal building. Many birds, too, are capable of such ‘super-flexible’ behaviour in emergencies.