Alpheus Hyatt Verrill, The boy collector’s handbook, New York, R. M. McBride, 1915, p. 144-145.
They may also be fresh-water sponges-for, strange as it may seem, there are sponges in fresh water- and there will almost always be some odd little cones, coils, and spheres formed of bits of sticks, tiny pebbles, etc. These will no doubt prove a puzzle and if they commence to move about- as they doubtless will- you will be still more at a loss to account for them. These strange objects are the little submarine homes of the larvae of insects called caddices flies. The adult insect are delicate, gauze-winged creatures which are often found ingreat swarms about eletric lights. The eggs are laid in or near the water and the larvae spend their lives on the bottom of streams and ponds. Each species builds a little home peculiar to its kind and while some are very roughly and carelessly made of bits of rubbish, others are really wonderful in their beauty and perfection of form. Some of the houses are like tiny, coiled, snail-shells ; others are formed like miniature elephant’ tusks ; others are almost globular, and still others are merely cylindrical in form. A great many are built up from small pebbles or grains of sand ; others are composed of tiny shells ; some species built their homes of bits of grass or straw so nearly fastened together that they resemble little bamboo cylinders, and one peculiar form of caddicefly home is formed of minute twigs or straws placed criss-cross like a tiny log-cabin (Fig .2).