142 BUTTERFLIES 



runs south through Wyoming and Utah to the corner of 

 Arizona, and thence east through New Mexico and Texas 

 to Ohio and West Virginia, extending south near the coast 

 to North Carolina. It thus includes a broad belt of terri- 

 tory occupying fully one half of the area of the United 

 States. 



Throughout this vast area the Silver Crescent is often a 

 purely local species, occurring abundantly during its brief 

 season in some favorable locality but seldom being seen 

 in other places near by. In the north it is single-brooded, 

 the butterflies appearing on the wing during June and 

 commonly disappearing early in July. Late in June the 

 females lay their eggs in clusters of a hundred or less on 

 the under surface of the leaves of various composite 

 plants, notably sunflowers, asters, and a common species 

 of Actinomeris. A week or more later these hatch into 

 little caterpillars that feed together in colonies upon the 

 green tissues of the leaf, taking only the succulent paren- 

 chyma and leaving the network of veins. As one leaf is 

 thus denuded they migrate to another, in this way passing 

 from leaf to leaf for several weeks in summer. They con- 

 tinue to feed until about half grown when they desert the 

 food plant and find shelter at the soil surface. Here they 

 become lethargic and hibernate until the following spring. 

 They then arouse again and feed upon the tender leaves of 

 the new growth, continuing to eat and grow for a few 

 weeks before they become mature as caterpillars and 

 change to chrysalids. A little later the chrysalids disclose 

 the butterflies which as already indicated appear in 

 June. 



In more southern regions the life-story of the species is 

 not so simple. There is at least a partial second brood and 



