When we examine the cases of the Basket-worm, hardly any two will be seen to be alike in their ornamentation. So completely is the outside covered, when made upon the arbor-vitæ, which seems to be a favorite food-plant of the species, that the silken envelope is concealed from view. The bits of twigs and leaves are probably protective, and yet one would think that the extremely tough case which covers the caterpillar would be quite sufficient to protect it against all assaults of foes and stress of weather. Nevertheless, this leafy coat of mail, which sometimes wholly covers the sac, must certainly add very much to the protective value of the covering. The caterpillar has a soft, hairless body, and is thus more exposed than many of its neighbors, and nature, it would seem, has favored it far above all of its fellows. How the worm manages to trim its coat in this manner must seem, to the uninitiated in such matters, wholly inexplicable. To enable the reader to understand the manner of operation, it will be necessary first to explain its mode of feeding. The larva has perfect control of its own movements, notwithstanding the fact that it carries its house upon its back. It can thus thrust its body out of the sac-mouth until nearly the whole of it is exposed, and twist and bend itself in every direction. Specimens have been met with that had dropped from the trees hanging by a thread and squirming, bending and snapping their bodies in the most grotesque ways, while the case spun around like an old-fashioned distaff. Now, when the caterpillar wants to feed it stretches its head and neck out of the case and moves them about until a satisfactory place has been secured, which it clasps with its true legs, three pairs of hard, conical organs armed with sharp claws, and pulls up its body and commences to spin. The spinning-organs are near the mouth, and after several movements of the head, as though smearing the liquid viscid silk upon the leaf, the head is drawn back, drawing out with it a short thread. A similar movement is then made against one side of the mouth of the sac, the process being repeated several times until a stout stay-line is spun by which the larva hangs securely. Now the creature is ready to feed. The behavior, however, varies a great deal. In feeding upon the white pine it secures itself to one leaf by its stay-line, while it reaches to an adjoining leaf which it bites off, and sitting erect, as it were, in its house, comfortably chews off the end which is continually shored upward by the first and second pairs of true legs that stand out free and untrammelled above the sac. [Illustration: HOUSE-BUILDER MOTH. Young in House, Winged Male, Young Suspended and Bag-like Female in Longitudinally-Split Cocoon.]