THE COMPLETE METAMORPHOSIS. 45 



The duration of the pupa state, like that of the 

 larval form, varies considerably in different insects, 

 but it is in this condition that most of our insects 

 pass through the winter. But whatever may be the 

 length of the period during which the insect is doomed 

 to remain in this death-like trance, and whatever may 

 be the peculiarities of its form, we know that a pro- 

 cess is gradually going on by which the different 

 organs are brought to their highest state of perfec- 

 tion, and when, at length, this condition is attained, 

 the creature bursts from the skin in which it had 

 passed its long period of inactivity, ready to perform 

 its part amongst the most active denizens of the air. 

 At first indeed its parts are comparatively soft and 

 weak, but this languid state quickly passes away, and 

 the insect then presents us with a perfect resemblance 

 of its parent. In this, its final state, it is denominated 

 an imago , as being the typical or perfect form of its 

 species. 



Such is the course of the metamorphosis observed 

 in those insects in which the young animal on first 

 leaving the egg presents the greatest difference from 

 its parent, this, from its great distinctness, is called 

 the complete metamorphosis. 



In the insects which exhibit this form of change, 

 the phenomena above described occur with great uni- 

 formity, although of course some of the minor cir- 

 cumstances may occasionally be modified; the most 

 important of these modifications is presented by cer- 

 tain insects whose larvae (maggots] undergo no change 

 of skin, and in which the change to the pupa state 

 takes place within the integument of the larva, which 



pupae of the Butterflies, many of which exhibit beautiful golden 

 tints upon different parts of their bodies. 



