William Houghton, Wonders near home, Londres, The Religious Tract Society, 1873, p. 33-34.
That is most interesting, « Ernest remarked; « and now, boys, let us hear what else you saw in your walk. » « Why, I saw a, lot of things that looked like bits of shell at the bottom of the water ; they moved slowly about; and see, I have brought you some specimens. » « Ah, said Ernest, « these are what are called caddis-worms; you see the creatures inside their homes, some of which are made of sticks, others of stones, or bits of grass or, rush; some of them appropriate small shells, and form them into houses. The caddis-worm are all the larva of a group of flies called Phryganidae (from phryganon, a greek word, meaning a stick), which live chiefly in wet and marshy places, near the edge of ponds and rivers; some are brown, others quite black. They fly in a zizag, trembling fashion.
Numbers are devoured by the hungry trout and grayling as they alight on the water for the purpose of depositing their eggs. Some kinds of caddis-worms fix their cases to stones and various other objects in the water; and when they are about to change into the pupa or chrysalis state they close the end with a kind of fence so as to allow the pupa to breathe, while the fence at the same time serves as a protection against invaders.