Anonyme, The Juvenile Instructor and Companion vol. XVII, Londres, William Cooke, 1869, p. 272-274.
Thus we find some kinds cutting various lengths from reeds or grasses, or else severing little leaves from water-lants, and forming pretty little cases, which look green and fresh. Others strange to say secure the tiny little shells with which our readers are familiar, and drag about with them the living litle occupants. Yet another species forms a horn-shaped case of grains of sand, which, with unwearied perseverance they glue together until they have amalgamated a sufficient quantity. In fact the variety of substances of which we find the cases of caddis worm formed is almost endless ; but, whilst this is to, the general plan is pretty nearly the same with all of the species.
In all instances, they employ a gummy substance to cement the various parts together, which substance is exceedingly firm, and resists the action of water, being insoluble therein. Then, again, their singular ingenuity in balancing or adjusting the weight of their little abodes should not pass unnoticed by us. Oftentimes they discover, whei the little building is completed, that its weight or its lightness is uncomfortable, preventing freddom of movement in the water, and thus fettering thezir actions. Should this be the case, they have resort to expedients which are indeed marvellous, and prove that they directed by Divine power, the Power which ever errs. If the case should be too light, a stone or shell is affiled ; or, if too heavy, a straw, piece of wood, or some other light substance
is fastened on it by thorn, or the heavy particles are removed, and light ones substituted. As the caddis-worm increases in size, it becomes vary evident that his abode will require enlargement. Thug we may find them gradually increasing and extending their little houses; now adding a little bit of wood here, and anon removing some incommoding piece there which could be dispensed with. Wonderful, indeed is the ingenuity which these little insects display in the construction of their aquatic castles ! Perhaps the most amusing thing about these little fellows is the fact that they are so well aware of the protection afforded by the walls of their little domiciles. If we keep somo of these creatures in an aquarium, and closely watch their motions in he water, and amongst its various objects, we shall be struck by the rapidity with which they withdraw at the least admonition of approaching danger.