42 STRUCTURE OF THE LEPIDOPTEBA 



construct a cocoon of chips of wood that it has bitten ont with its 

 powerful jaws, all joined together into a hard shell by means of 

 transparent glne. Shut another Puss in a glass vessel — a tumbler, 

 for instance — either by placing it under the inverted vessel, or by 

 covering over the top. Perhaps it will not be superfluous to men- 

 tion that, should you place it under an inverted vessel, this vessel 

 should not stand on a polished table, for, whatever be the material, 

 unless extremeljj hard, it is sure to be utilised in the manufacture 

 of the cocoon. 



Let us suppose, then, that the caterpillar is under an inverted 

 tumbler that stands on a plate or saucer. Now it is for you to 

 decide what material shall be used in the construction of the new 

 home. Give Puss some fine strips of brightly coloured ribbon, 

 and it will construct a very gaudy house by gluing them together. 

 Or, provide it with sawdust, pieces of rag, glass beads, sand, paper, 

 anj-tliing in fact ; and the material will be ' made up ' into a 

 cocoon more or less ornamental according to the nature of the supply. 



But what if you give it nothing with which to work, and so 

 inclose it that nothing its jaws can pierce is within its reach ? 

 For instance, shut it in with tumbler and saucer as before, invert- 

 ing the former on the latter, and give it no material whatever. 

 What will it do now ? We will watch and see. 



At first it is very restless, and walks round and round the edge 

 of the tumbler, evidently a little dissatisfied with the prospects. 

 Then, after a little while, the events of nature transpiring in their 

 fixed order regardless of trivial mishaps, the glutinous fluid begins 

 to flow from the creature's spinning glands, and it moves about in 

 a somewhat aimless fashion, applying the traiisparent adhesive 

 matter both to tumbler and saucer. 



It seems now to become a little raore reconciled to its unnatural 

 surroundings ; and, making the best of bad matters, keeps itg 

 body in one place, and starts the construction of a ridge or barrier 

 all round itself. By the continued application of the creature's 

 spinneret this barrier is made gradually thicker and higher, till at 

 last tlie overhanging sides meet and the caterpillar is inclosed in 

 its self-constructed prison. But the walls of this prison are so 

 transparent that every movement can be watched ; and, after the 

 insect has spent a few days in completing the cocoon, we can see 

 it cast off its old skin, and appear in the new garb of a fine 

 greenish chrysalis. 



Its soft "reen skin soon hardens and turns to a rich dark brown 



