Edwin Lankester, Science from an easy chair, New York, The MacMillan, 1911, p. 343.

Nature to it is the case made by the aquatic grubs or caterpillars of another kind of insects-the caddis-worms (« case-worms ») which are common in ponds and streams. They show extraordinary powers in making their cases so that they balance nicely in the water, as the animal crawls along on the bottom of a pool, with his head and six legs emerging from one end of the case. Caddis-worm are of various kinds or species, and some attach to their cases little broken sticks, others minute empty snail-shells, others the fine green threads of water-plants. The caddis-worm becomes changed into a delicate fly, with transparent wings, just as the clothes-grub becomes changed into a moth- and it is an interesting fact that the caddis-flies , though they ara classed with the Mayflies