ANIMAL LIFE 



ling one. But we know that development in other animals 

 is a gradual and continuous process, and so it is in the 



case of the butterfly. 

 The gradual chang- 

 ing is masked by the 

 outer covering of the 

 body in both larva 

 and pupa. It is only 

 at each molting or 

 throwing off of this 

 unchanging, unyield- 

 ing chitin armor that 

 we perceive how far 

 this change has gone. 

 The longest time of 

 concealment is that 

 during the pupal or 

 chrysalis stage, and 

 the results of the 

 changing or develop- 

 ment when finally re- 

 vealed by the split- 

 ting of the pupal 

 case are hence the 

 most striking. 



58. Metamorphosis of the toad. Metamorphosis is found 

 in the development of numerous other animals, as well as 

 among the insects. Certain cases are familiar to all the 

 metamorphosis of the frogs and toads (Fig. 46). The eggs 

 of the toad are arranged in long strings or ribbons in a 

 transparent jelly-like substance. These jelly ribbons with 

 the small, black, bead-like eggs in them are wound around 

 the stems of submerged plants or sticks near the shores of 

 the pond. From each egg hatches a tiny, wriggling tad- 

 pole, differing nearly as much from a full-grown toad as 

 a caterpillar differs from a butterfly. The tadpoles feed on 



FIG. 45. Larva of a butterfly just changing into 

 pupa (making last larval molt). Photograph 

 from Nature. 



