Anonyme, Insects and their Habitations, Londres, John W. Parker, 1834, p.67-68.
There is a very interesting class of grubs which live under water, well-known to fishermen by the name of case, or caddis-worms. They form moveable tents of various substances. One glues leaves together into a very pretty case ; another uses reeds or straws, cut into bits, and joined carefully together, with one piece longer than the rest, placed over the opening, to shade its head, and prevent its being seen; a third makes choice of fresh water shell-fish and snails, and forms a complete grotto, which it carries about, keeping these poor creatures close prisonners; a fourth makes its abode of small stones, and it is curious to see how carefuly these are chosen, so as to make the inside quite smooth and even, and the bottom flat; that it may be dragged along easily. If you recollect how full pebbles are of sharp corners, and rough edges, you will see how very hard a tas kit must be to choose out such as will suit the purpose. Yes by patiently turning them on every side, the insect at last succeeds. If the materials prove so light that there is danger of being swept away by the streams, a larger stone is added by way of ballast; if, on the contrary, the case should prove too heavy, a hollow straw or some light thing is added, to keep it up.