SEASONAL CHANGES AND HISTORIES. 133 



the season than almost any other single-brooded 

 butterfly ; the conditions, however, under which 

 it passes the winter are common to many of our 

 butterflies. 



We have already stated that the Viceroy [see 

 Fig. 84] hibernated as a caterpillar ; but there 

 are some interesting features in its history which 

 may now be related. Quite as soon as there is a 

 morsel of food to eat on the twig which has been 

 its winter home, it forsakes its retreat in the 

 curled leaf, and breaks its long fast. The butter- 

 flies developed from the wintering caterpillars 

 appear early in June, become abundant by the 

 middle of the month, and continue for another 

 fortnight to emerge from the chrysalis ; about a 

 month after the first appearance of the males the 

 females begin to lay eggs ; the caterpillars soon 

 hatch and grow rapidly, and late in July change 

 to chrysalis ; in this state they continue about 

 eight days, and before the middle of August a 

 new brood of butterflies is abroad. The caterpil- 

 lars from eggs laid by this brood are those which 

 construct the little hibemacula wherein they find 

 protection from the wintry cold ; no trace of any 

 tendency to construct such habitations appears in 

 the caterpillars of the first brood ; here we have 

 an instinct inherited by alternate generations ; or 

 only when the nightly chills or the desiccating 

 food indicates the coming of an unfriendly season. 



