John Clegg, Life in ponds, Nature Treasure, Series, Book 6, Londres, Frederick Warne, 1952,
In your pond-hunting you are sure to coma cross the strange little cases made by the larvae of caddis flies. Some are made of sticks, some of stones, others perhaps of shells and still others of grains of sand . A few kinds are shown in the picture. Each case has an inner lining of silk, and the sticks, stones or whatever material is used, are stuck to that. If you want to dislodge a larva from its case you can do so by tickling it with a pin head at its tail end. It will then often leave the case and, if you give it a supply of new material, make a new one while you watch it. These cases serve not only as portable homes for the soft-bodied little large within them but also as shelter from some of their ennemies. I am sorry to say, however, that greedy trout gobble up the caddis larvae, case and all!