FOSSIL BUTTERFLIES. 757 



Three of the four families of butterflies are represented in tliis meagre 

 little collection, tiie smaller butterflies of the fomily Lycaenidae being 

 unknown in a fossil state in the rocks, though it is rather vaguely reported 

 that they have been found In amber. The largest number (9) arc Nym- 

 phalidae, the next (4) Papilionidae, while the Hesperidae have only two 

 representatives. All but one of the seven American species, however, 

 belong to the Nymphalidac ; that exception to the Papilionidae. 



These meagre statistics may have a certain interest ; but it is of more 

 importance to inquire how far the fossils diflfer from existing forms, and what 

 they teach us. For this i)urpose let us examine the European and Amer- 

 ican forms separately, and turn our attention first to the nine European 

 species, omitting the caterpillar from Aix which is thought to be one of 

 the Satyrinae, to which subfamily two of the five Aix specimens belong. 

 All these European forms have been subjected to a severe analysis. 



To begin with the highest and pass downward, we have first two Saty- 

 rids, a group now represented by the dark brown butterflies of our mead- 

 ows ; the nearest allies of both of these, Neorinopis and Lcthites, are now 

 restricted to the Indo-Malayan region, and are much more gaily attired 

 than the present sombre representatives of the subfamily in Europe. 

 Their food in the larval state has invariably been found to be either 

 grasses, or, occasionally, with the more arctic or alpine forms, sedges. In 

 the Aix deposits, as in the Indo-Malayan region to-day, these plants are 

 numerically unimportant, so that if we may form any opinion from such 

 meagre data, we find that while oligocene Aix had a European propor- 

 tion of Satyrids, they were composed of species of an Indian aspect and 

 fed upon plants characteristically temperate, but, as in tropical countries, 

 numerically unimportant . 



The remaining Nymphalid is the Eugonia from Eadoboj. This is more 

 nearly related than any other to the mass of the Florissant fossils. It 

 belongs to an existing genus represented to-day equally in Europe and 

 America, but with a fuller development of neighboring genera in the Kew 

 World, showing that its affinities are with the New rather than with the 

 Old World ; its food in early life was probably some species of elm, wil- 

 low, poplar or birch, and species of all these genera have been found in 

 the same beds. 



Passing to the Papilionidae we find three Pierinae and one Parnassian ; 

 two of the three Pierinae are allies of our common brimstone yellow butter- 

 flies, and the third to our white spotted cabbage butterflies. The former, 

 however, Mylothrites and Collates, belong to distinctly tropical types, 

 referable again to the Indo-Malayan or Austro-Malayan regions ; their 

 larvae doubtless fed on leguminous plants, which have been found in 

 abundance both at Aix and Kadoboj from which these species come. The 

 white butterfly belongs to the existing genus Pontia, whose present geo- 



