150 SEASONAL CHANGES AND HISTORIES. 



tions without lethargic retardation, and the but- 

 terflies which emerged in the autumn laid eggs ; 

 if eggs were laid, we may presume they hatched, 

 and the young caterpillars hibernated. 



If now we suppose a shorter season, such as 

 actually exists in some parts of our country 

 where this butterfly occurs, undoubtedly the first 

 change would be the entire elimination of the 

 September butterflies and the hibernation of all 

 the vernal caterpillars when half grown ; this is 

 probably the actual state of things 

 in parts of Canada ; still farther 

 north these caterpillars would prob- 

 ably by degrees hibernate when first 

 born, and we should then be trans- 

 ported to the simple condition which 

 prevails in the larger fritillaries 



Atlantis, Bat. size. ,--.-,. -, -, -, n * -, , 



[Fig. 133], and have only one flight 

 of butterflies in the season. 



What may be the exact climatic features which 

 determine the number of generations of a butter- 

 fly has not yet been studied ; but there are som 

 curious difficulties in the way of understanding 



special inquiries he afterward informed me), and this gives his 

 account an entirely different appearance. It is to be regretted 

 that this able and industrious observer has since then given the 

 history of other butterflies without informing us whether they 

 were reared in New York or West Virginia, in both of which 

 regions, four degrees of latitude apart, he is accustomed to rear 

 insects. 



