THE EMPEROR AND ATLAS MOTHS. 299 



been placed there by some kind friend, I set it, and watched the 

 cocoon as usual. After a whole year had passed, I thought that 

 there must be something wrong, and so took out the cocoon and 

 carefully cut it open. 



The mystery was at once explained. "Within were the cast 

 shell of the chrysalis, and the dried, shriveled skin of the cater- 

 pillar, crushed up into a very small space, but recognizable by the 

 hairy tufts. The manner in which the moth had escaped was 

 also evident. Taking as our model a common Florence oil-flask, 

 from which three fourths of the neck have been removed, we 

 shall obtain a clear notion of the method by which the cocoon is 

 made, so as to allow the egress of the moth, and at the same time 

 to show no aperture through which the creature had emerged. 



Let us suppose the material to be stiff, bristle-like hair, and 

 that the body of the flask is made stiff and firm by cementing the 

 hairs together, while they project loosely at the neck. Now let 

 us farther suppose that these projecting hairs are all bent inward, 

 so as to cross each other slightly, and we shall have a tolerably 

 correct idea of the manner in which the cocoon of the Emperor 

 Moth is made. It will be seen that, if a creature try to push its 

 way out from the inside, the hairs will yield and allow it to pass, 

 but that if any insect tries to push its way in from the outside, 

 the converging hairs are pressed tighter together, and effectually 

 debar it from gaining admission. 



This beautiful structure is not visible until the observer strips 

 away a thick, loose coating of yellow- white silk which covers the 

 cocoon, and probably acts as a non-conductor of heat as well as a 

 protection from the weather. This cocoon may be found upon 

 the plant on which the insect feeds, but the best method of pro- 

 curing perfect specimens is by searching for the caterpillars and 

 feeding them until they change. 



Ox the right hand of the accompanying illustration may be 

 seen a large moth flying downward, and just above it are a couple 

 of oval objects attached to a slender bough. This moth is that 

 magnificent insect the Atlas Moth (Saturnia Atlas), and the 

 oval objects are the cocoons which are spun by its larva. 



The Atlas Moth belongs to the same genus as the emperor 

 moth which has just been described, and is a truly splendid in- 

 sect, though without the beautiful colors which decorate the em- 

 peror. Creamy white, soft yellow, and pale brown are the chief 



