128 Life and Immortality. 
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-vite, 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 inex- 
plicable. 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 move- 
ments, 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 com- 
mences 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 
