They are funny fellows these cads

Robert & A.M. West, « Fresh and Salt-Water aquaria », Report of the Commissioner of Agriculture for the year,Washington, Government Printing Office, 1864, p. 458-459.

The aquatic larvae supply many interesting subjects for the aquarium. But if we wish to observe correctly their remarkable habits and transformations we should give them a home of their own- a tank to themselves- or they will fall a prey to the voracity of the fishes. The caddis worm, the larva of the order of Phryganeae is first among these, and its habits are worth very close inspection. By means of a silky secretion it forms for itself a sort of sheath or case, consisting of bits of wood, small pebbles, sand, portions of leaves, and fragments of the shells of water snails. Protruding the forepart of the body from this singular tenement it crawls all over the aquarium moving with far greater activity than would be supposed. It is very voracious, however, and carnivorous in its appetite, and is only tolerated in the aquarium because otherwise we could never know its wonderful powers. Mr Edwards justly says that « without the glass sides of the aquarium we would not be able to see the caddis worms build their grottoes and go through their metamorphoses. They caddis worms build their grottoes and go through their metamorphoses. They are funny fellows these cads. I have some that have cases built by laying three sticks across each other, so as to form a triangle ; upon this another triangle of sticks is built, but a little shifted; the next a little more so, and so on, until we have a case with a rough and pointed exterior covered with projecting sticks, but a comfortable and beautiful smoothness within. I have others that five-sided cases » He adds, that « instead of forming their cases pf leaves of sombre Brown hue, they will make one-third of its length of dark colored leaves, the next of light colored, and the next of green. » In this latter remark Mr Edwards has, I think, judged only by what he has observed in his aquarium. I have seen them by hundreds in streams, and have captured not a few, but uniformly found the case of a color most nearly resembling the mud at the bottom of the brook. In the aquarium the case will be repaired or patched with green, no other color being at hand. I have watched diligently the making and repairing of the cases, but the exact modus operandi remains as much a secret to me as ever. No skilful tailor ever made repairs so neatly as Mr Caddis. The patch appears to be first stuck on from the outside, the adhesion being in the centre only, and the edges very perceptibly standing off from the garment under repair. But the worms works from the inside, and in a very brief time the new piece is so perfectly interwoven with the old that, with a powerful magnifying glass he looks almost as forlorn and miserable as the hermit crab of the marine tank in similar circumstances.