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-vitae, 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 



