336 INSECT TRANSFORMATIONS. 



insect is not bigger than a small pea, while the fly is 

 nearly an inch in length, and the expanse of the wings 

 about two inches. 



In some aquatic insects this transformation is the 

 more conspicuous from the change of element, the 

 pupa emerging into the dry atmosphere, where the fly 

 is evolved. In the case of the dragon-flies just men- 

 tioned, the approaching change is evinced by the 

 increasing transparency of the pupa, exhibiting the 

 growing brilliancy of the large lustrous eyes of the in- 

 cluded insect, which may be then brought into view 

 by removing the envelope. At this period it may be 

 seen removing out of the water to a dry place, such 

 as a grassy bank or the stems of aquatic plants, into 

 which it pushes its sharp claws, and remains for a 

 short time immovable. By the swelling of the 

 upper part of the body the envelope is soon distended 

 and burst asunder on the back of the head and 

 shoulders, and, through the opening, first the head 

 and then the legs of the perfect fly make their exit, 

 whilst the empty slough of the legs continues fixed 

 in its place. After this first part of the process is 

 accomplished, it hangs down its head and rests for 

 a space, as if exhausted by previous exertion, or 

 rather to allow the newly excluded parts to dry and 

 become more firm. It next erects itself, and laying 

 hold of the upper part of the slough with its feet, 

 pulls the parts still enveloped further out, then 

 creeping forward by degrees, it disengages the en- 

 tire body, and again rests for a time immovable. 

 The wings now begin to expand themselves, and 

 their plaits and folds become gradually smooth. 

 The body, also, becomes insensibly larger and 

 longer, and the limbs acquire their just size and pro- 

 portions. While the wings are undergoing this 

 operation of drying and expanding, the insect takes 

 care to keep them from coming into contact with the 



