Andrew Wilson, Leaves from a Naturalist’s Note-Book, Londres, Chatto & Windus, 1882, p. 250.

The Caddis-worms are in the phial at your elbow. And they desserve a word in passing. That is the larva or grub of the Alder-fly, dear to the heart of the angler.You see, by aid of the lens, its jaws, its six feet, and its seven pairs of curious gill-plumes, adapting it for an aquatic type of breathing. Here are your true Caddis-worms, well-know to Aristotle himself, and near relations of the big dragon-flies that sweep continually over the pond younder. Gluing together bits of sticks, fragments of gravel, and grains of sand, and other odds and ends to be picked up in its native waters, these baby-insects pass their time in the active pursuit of the water-fleas, and live merrily enough in the bed of the clear-running brooks around. When maturity and its cares dawn upob the Caddis-worms, the mouth of the case is closed by a silken grating, spun, as are the threads which bind its materials together from a silken gland placed in the mouth. Then the case ruptures, and the winged insect, having passed through its chrysalis state in the sillent retirement of its abode, appears on the scene, henceforth fiscarding the waters and leading the aerial life of its kind. To watch the Caddis-worms is, in truth, no uninteresting study for part of a summer holiday.