218 NATURAL HISTORY. [CH. XII. 



These rents are brought about by a power which 

 the insect possesses of inflating its body and head. 

 This last organ, ultimately destined to become fixed 

 and solid, is at this period capable of contraction 

 and dilatation, like a membrane. 



The head and corslet being exposed, the legs are 

 drawn out from their nymphine cases. At this period 

 every part of the insect is soft. The four figures in 

 the preceding page illustrate its mode of exit. 



In the first (Jig. 1), it is partially out; in the se- 

 cond (fig'. 2), after having protruded itself thus far, 

 it hangs with its head downwards, and remains mo* 

 tionless, so as to lead the observer to believe that 

 the efforts which it had hitherto made had exhausted 

 its strength, and that it had thus perished in the act 

 of being born. However, it remains in this position 

 just so long as to permit its body and limbs to be 

 hardened and dried by the air, and then it reverses 

 it to that of fig. 3, forming anarch ; this enables the 

 insect to draw out its tail from the mask. 



When it has just cast off that tenement in which 

 it had till now existed, the body of the libellula is 

 soft, has not attained its full length, and the wings 

 are still folded. It remains, therefore, tranquil and 

 motionless till these important operations have taken 

 place, which are finished sooner or later, according 

 to the heat or moisture of the atmosphere. The 

 operation may be completed in a quarter of an hour, 

 or take up several hours, according to circumstances. 

 The wings unfold themselves in every direction ; 

 it is supposed that this curious mechanical effect is 

 brought about by means of the fluids, which rush 

 into and distend them ; for they remain drooping as 

 wet paper if the insect die in the act of metamor- 

 phosis ; so that something more than drying is ne- 

 cessary. During the time that the wings, from 

 being shrivelled and flexible, are becoming firm and 

 glistening as talc, the dragon-fly takes care not to 

 allow even its own body to obstruct their expansion 



