Rev. William Houghton, Country walks of a naturalist with his children, Londres, Groombridge, 1869.
Here we are at a stream ; do you see those things at the bottom sowy moving ? They seem to be bits of stick. « I know what they are, » said Jack, « there is a good fat magot in cach of these cases ; they are caddis-worms. » Quite right, and in time they will change to insects. Here is another kind ; the house is made of small bits of gravel, and it is attached to smooth stone. I will break open the case ; do you see Inside is a long cylindrical case, with my penknife, and now you see the creature Inside. There are a great variety of these caddis-worms, and most interesting it is to nitice the different kind oh houses they build. Some of the larvae live in movable cases, as we have seen some in fixed habitations ; the materials, too, out of which the different cases are coonstructed, are different, sometimes they are bits of gravel, or sands, wood, leaves, grass, the empty shells or various frehs-water molluscs. The fragments of stick and the small bits of gravel are held together by a kind of cement which the larva spins from his mouth.
Sometimes we may meet with cases made of sand, having on either side long slender bits of rush or stick. A lady once took a number of the larvae out of their cases, and placed them in a vessel of water with various materials, such as coloured glass, cornelian, agate, onyx, brass filings, coralline, tortoiseshell ; and these little maggoty things made use of and built their houses out of them.