124 BUTTERFLIES 



the common tent caterpillar which becomes a fully formed 

 caterpillar within the egg shell before the end of autumn, 

 but remains unhatched until the following spring. In the 

 present case the caterpillar hibernates outside of the egg 

 shell rather than within it. 



When at last the warm sunshine of spring starts the 

 violets into new growth the tiny caterpillars begin feeding 

 upon the succulent tissues. They nibble away day after 

 day for a week or more before they become so large that 

 they have to cast their skin for the first time. They then 

 feed again and continue this process of feeding and moult- 

 ing until early in summer. They are likely to hide them- 

 selves during daylight and have the reputation of being 

 difficult to rear under artificial conditions. 



The full-grown caterpillar wanders along the surface of 

 the ground in search of suitable shelter for the chrysalis 

 period. When it comes to a large stone with sides pro- 

 jecting more or less horizontally or a log lying upon 

 the ground or even a large piece of loose bark it is likely 

 to stop and change to the pupa or chrysalis. In this con- 

 dition it is dark brown in color and well covered with 

 thickened tubercles, especially along the back of the 

 abdomen. 



About a fortnight later the chrysalis breaks open and the 

 fully developed butterfly comes forth. It rests quietly for 

 a time while its wings expand and the tissues harden and 

 then sallies forth for its long period of flight; for this insect 

 is single-brooded in the Northern states at least and the 

 butterflies that thus mature late in June or early in July 

 are likely to remain alive until early in September. So 

 they have a comparatively long life for a butterfly that 

 does not hibernate as an adult. 



