26 BUTTERFLY METAMORPHOSES. 



are driven from the internal vessels into all the tubes and 

 nervures of the wings, which being at the same time filled 

 with air from the wind-pipe, increase considerably in size. 

 This, added to the restless motion of the legs, soon enables the 

 imprisoned creature to bnrst its enshrouding skin, which, 

 flying open at the back, discloses the head and shoulder of the 

 butterfly. Being then soon released entirely, it stands for 

 awhile, motionless, on the broken fragments of its late prison 

 its wings damp and drooping, small and crumpled ; but dis- 

 tended by the fresh supply of air, inhaled through the spiracles, 

 they expand so rapidly, that in the space of a few minutes 

 their dimensions are increased five-fold ! 



Nothing can be more curious and interesting than to watch 

 this marvellous expansion; and, as the crumpled membrane of 

 the wing grows smooth, to discern, emerging slowly from a 

 chaos of mingled hues, all the clearness of pattern and 

 brilliancy of colour which bespeak it finished. As we gaze 

 with admiration on this process of perfection, we seem to have 

 gained admission for the moment into one of nature's studios, 

 and to be tracing the progress of her unrivalled pencil, while 

 employed (under the guidance of her Divine Master) on tin 

 last touches of what have been justly considered as her 

 favourite miniatures. In half an hour the pictured pinions 

 are complete. 



Directly after emergemeut, the wings are thick, and capable 

 of great extension by stretching, but not so after full ex- 



