VAPORER MOTH COCOON. 211 



formed of whitish silken threads so loosely woven together that 

 the enclosed chrysalis can often be seen. They consist of an outer 

 and an inner covering or tunic. The outer covering is commonly 

 formed in part of two leaves, which are bent and tied together 

 in such a manner as to make a kind of roof, sheltering the co- 

 coon from rain, the lower leaf being overlapped by the lower 

 edge of the upper one. There is considerable diversity, however, 

 in the mode in which the leaves are attached to the cocoon. 

 Sometimes they are drawn around it in the form of a cone with 

 its point upwards. Sometimes but a single leaf is used. I once 

 met with one of these cocoons upon the upper surface of a but- 

 ternut leaf, the sides of which were drawn upwards so that the 

 leaf formed half of the exterior portion of the structure. And 

 as if the worm was aware of the brittle attachment of the leaf 

 to the main stem, and was conscious that its own weight added 

 to that of the leaf would inevitably cause it to break off and 

 fall should a gale of wind arise, it had spun several threads to 

 the main stem, thus securely tying it thereto. It is impossible 

 for us to conceive how this worm came to possess such know- 

 ledge. The main stem would have fallen with the fall of the 

 leaves in autumn. This cocoon produced a male moth. The 

 female caterpillars undoubtedly place their cocoons, in every 

 instance, where they will remain upon the tree through the win- 

 ter; whilst the males are indifferent in this matter, caring for 

 their safety only for the short time they remain withiu them. 

 This is a signal instance of the harmony of nature, as will ap- 

 pear when we come to see where the eggs of the female are de- 

 posited. 



Woven into the cocoon are numerous black and pale hairs, 

 derived from the body of the caterpillars; and the remains of 

 plant-lice are sometimes interspersed, probably from these stu- 

 pid creatures having wandered over the cocoon at the time of its 

 construction, and becoming inextricably involved in its meshes. 

 The cocoon is about an inch and a half long. The inner tunic 

 is but half the size of the outer, the space between being occupied 

 with single threads crossing each other in every direction, and 

 with the shrivelled remains of the caterpillar lying in the lower 

 end. This inner covering is a closed sack of a regular oval form. 



