OF THE PAST 273 



among the plants, there is a growing likeness to 

 American types as we pass upward through the 



tertiaries. 



The American fossil butterflies, fewer in num- 

 ber, less varied in character, and all from one 

 locality, Florissant, are more quickly reviewed. 

 They all belong to extinct genera. Seven of the 

 eight belong to the Nymphalidae, and all but two 

 of" these to a single tribe, Vanessini, of the sub- 

 family Nymphalinae. Of these, three, Prodryas, 

 Jupiteria, and Lithopsyche, form a group by them- 

 selves, more closely allied to one another than to 

 any living forms, but having distinct affinities to 

 certain butterflies of Central and generally sub- 

 tropical America. A fourth, Nymphalites, is re- 

 lated to them, though not very closely, and it, too, 

 finds closer relations among Central American 

 butterflies. The fifth, Apanthesis, is still farther 

 removed, and is related, as closely as to anything, 

 to a tropical American group of butterflies geo- 

 gi-aphicaUy isolated, all of its iimnediate relations 

 being East Indian. Of none of the butterflies to 

 whiek all of these Nymphalinae are allied is the 

 food plant of the caterpillar known. 



The other Nymphalids, Prolibythea and Barba- 

 rothea, are of special interest, for they belong to 



