BUTTERFLIES AND MOTHS . 
49 
Finally, the larva seems to have eaten enough. It 
brings to a close its life of unceasing feeding and pre¬ 
pares for a period of sleep. Often it spins a silken 
cocoon in which it rests throughout the winter; some¬ 
times it hangs by a single thread to a rock or fence- 
rail, its exoskeleton making a beautiful chrysalis 
ornamented with spots 
of burnished silver, jet, 
and gold; again it buries 
itself in the ground to 
await the genial warmth 
of returning spring. In 
any case it takes no 
food and seldom moves, 
but within its body 
changes progress, until 
the full-grown butterfly 
or moth breaks through 
the hard case of the 
pupa, stretches and 
dries its wings for a 
short time, and flies 
away for its brief period 
of aerial life. 
The full-grown but¬ 
terfly, or imago, no 
longer eats the coarse 
food familiar to its lar¬ 
val stage. In fact, it 
could not do so if it 
would, for its mouth is 
no longer fitted for biting, but is provided with a long 
proboscis with which it sucks honey from its favorite 
flowers. This series of changes is known as com¬ 
plete metamorphosis (Fig. 50). 
Structure of the Proboscis. The proboscis is a 
curious organ and well repays careful study. It is 
composed of two long half-tubes which are produced 
Fig. 50.—A Cabbage-butterfly, «, 
larva; b, pupa; c, egg; d , imago. 
