564 William Reifj 



son. We should expect, therefore, to see the two generations of J. 

 coenia taking on a seasonal dimorphism in their northern range, 

 and the causes of this would be just the opposite of those which 

 have operated in the production of the seasonal dimorphism of 

 the European Araschnia levana L. Concerning the importance 

 and origin of the seasonal dimorphism in this latter species, A. 

 Weismann has given an extended and clear account in his "Stu- 

 dien zur Descendenz-Theorie," Leipzig, 1875. 



I am, therefore, of the opinion that the coenia which I obtained 

 from experiments with cold, show the direction which the colora- 

 tion and markings of the winter form will take in future time, if 

 the pupa should acquire the ability to hibernate. That this time 

 is still very far distant, is shown, for example, by Doll's collection 

 of coenia, which among its great riches, shows only one specimen 

 that approximates to the cold forms. 



If we now bring together what has been shown by the experi- 

 ments with warmth and cold, we come to what is certainly the 

 correct conclusion, that |. coenia Hb. is about to produce a local 

 form in its southern range, and that in its northern range it will 

 bring forth a seasonal dimorphic species after a considerable period 

 of time if the pupa, instead of the imago, should acquire the ability 

 to hibernate. 



A few words may be said about the melanistic form of junonia 

 coenia, the ab. negra Felden. Through the kindness of Mr. Doll, 

 of Brooklyn, and Mr. H. H. Newcomb, of Boston, I have been 

 able to examine a fine series, together with transitions, of this 

 aberration, which is known only from the southern and south- 

 western range of the species. Its origin in nature is probably 

 to be traced to extremely dry heat acting on the pupa, but this can 

 only be decided by further experimentation. It is certain, how- 

 ever, that negra is not to be placed in the same group with the 

 darker cold forms, since even in the most strongly melanistic speci- 

 mens the eye-spots are still distinct and of normal size, whereas 

 in the cold forms, even in light-colored specimens, there is always 

 a diminution or incipient dissolution of these spots. Whether 

 it would be right to regard the ab. negra as a partial reversion to 

 J. genoveva, I will not undertake to decide. Apart from the 



