Emperor-Moth. 343 



by the convergence of little bundles of silk, gummed together, 

 .and almost as elastic as whalebone. In consequence of all 

 these terminating in needle-shaped points, the entrance of 

 depredators is guarded against, upon the principle which 

 prevents the escape of a mouse from a wire trap. The insect, 

 however, not contented with this protection, constructs an- 

 other in form of a canopy or dome, within the external aper- 

 ture, so as effectually to shield the chrysalis from danger. 

 We have formerly remarked (page 210) that the caterpillar 

 of the Algeria asiliformis of Stephens in a similar way did 

 not appear to be contented with a covering of thin wood, 

 without an additional bonnet of brown wax. The cocoon of 



Cocoons of the Emperor-moth, cut open to show their structure. 



the emperor-moth, though thus in some measure impenetrable 

 from without, is readily opened from within ; and when the 

 moth issues from its pupa case, it easily makes its way out 

 without either the acid or eye-files ascribed to the silk-worm. 

 The elastic silk gives way upon being pushed from witjiin, 

 and when the insect is fairly out, it shuts again of its own 

 accord, like a door with spring hinges, a circumstance 

 which at first puzzled Eoesel not a little when he saw a fine 

 large moth in his box, and the cocoon apparently in the same 

 state as when he had put it there. Another naturalist con- 

 jectures that the converging threads are intended to compress 

 the body of the moth as it emerges, in order to force the 



