94 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- 
ee he et ce | Vealed by the split- 
Fig. 45 —Larva of a butterfly just inane into ting of the pupal 
Vis ee last larval molt), Photograph 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 
