THE COMMON BUTTERFLIES 



219 



THE LIFE HISTORY OF A BUTTERFLY 

 The life-history consists of four stages : 



First. — The eggs which 

 are laid upon the food 

 plant by the mother but- 

 terfly; these eggs are often 

 exquisite in color and beau- 

 tifully ribbed and pitted so 

 that when seen through the 

 microscope they look like 

 gems. 



Second. — The caterpillars 

 which hatch from these eggs 

 and which feed upon the 

 food plant until fully developed 



Eggs of Black vSwallowtail, enlarged. 



Before reaching its full growth, 

 the caterpil- 

 lar sheds its 

 skeleton- skin 

 four or five 

 times ; often 

 this change of 

 skin makes a 

 change in the 

 appearance 

 and in the 

 color of the 

 caterpillar. 

 Third.— The 

 pupa state or 

 chrysalis. 

 When the 



caterpillar is full grown it sheds its old skin and appears in a very 



different form, that of the 



chrysalis or pupa. The 



pupae of the butterflies are 



never protected by a cocoon as 



are the pupas of moths. This 



is one of the chief difl'erences 



between moths and butter- 



Caterpillar of Black Swallowtail in two stages of growth. 

 The larger one has the scent organs protruding. 



Chrysalis of Black Swallowtail 



