THE TRIBE OF THE CRESCENT-SPOTS 141 



fields about the middle of June. They are often very 

 abundant and are much more generally distributed than 

 the Baltimore Checker-spot. A few weeks later the fe- 

 males lay their eggs upon the aster leaves, the eggs being 

 deposited in clusters of twenty or more on the under side 

 of the leaf. Early in July the little caterpillars come forth 

 and remain together in colonies as they feed upon the 

 green tissues of the leaves. Each is able to spin a silken 

 thread so that wherever they go they weave a web and 

 they soon protect themselves with a slight silken shelter, 

 which is suggestive of the nests made by the Baltimore cat- 

 erpillar. They continue to live in this manner for several 

 weeks in July and August, growing rather gradually and 

 becoming approximately half grown before the frosts of 

 autumn. Unlike the Baltimore caterpillars they now de- 

 sert their nests and find shelter at or near the surface of the 

 ground. Here they hibernate, to come forth the following 

 spring and feed again upon the new growth of the aster 

 plants, often doing considerable damage by denuding the 

 young shoots of their leaves. They become full grown in 

 time to change to chrysalids so that the butterflies may 

 emerge in June. 



The Silver Crescent 



Charidryas nycteis 



While this species has not the broad distribution for wliich 

 the Pearl Crescent is notable it occurs over a large part of 

 the United States. Its distribution is bounded broadly by 

 a line running from southern Canada north of Maine to a 

 point in southern Canada north of Montana, whence it 



