70 OF THE PUPA STATE. 
After remaining for some months in the pupa 
condition, the skin or casement bursts, and the 
creature then emerges in its perfect or Jmago state. 
This term was employed by Linnaeus, from its hay- 
ing laid aside its mask, or swaddling clothes, and 
become a true image of its species. 
Butterflies, in their perfect form, have only six 
feet, ten of those with which it was fwnished in its 
caterpillar state having disappeared. The jaws, also, 
are lost, and replaced by a curled-up proboscis, in- 
capable of mastication, and only suited for extract- 
ing the liquid sweets from flowers. The head is 
totally changed in form; and it has acquired four 
wings, to enable it to make rapid and extensive 
aérial flights. Two long horns project from the 
upper part of its head, and its twelve eyes are re- 
placed by two, which are composed of at least 
twenty thousand convex lenses, each supposed to 
possess distinct and effective vision. 
The internal change of structure is no less asto- 
nishing than that which is presented externally. In 
the caterpillar, there are some thousands of muscles, 
which are replaced in the Imago by others of a form 
and structure entirely different. Almost the whole 
body of the caterpillar is occupied by a capacious 
stomach. In the butterfly, this changes into an 
almost imperceptible thread-like process; and the 
abdomen is inflated by two large packets of eggs, or 
other organs, which are not visible in its former con- 
