438 THE BLTTERI'LIES OF NEAV ENCiLAND. 



hemisphere (more abundantly in the Old A^^)l■ld than in the New), it is dif- 

 ficult to form any [)ro})er juduinent concerning its place of origin, thoug'h 

 it would ap[)ear more })robalde on general grcmnds that it originated in the 

 Old ^Vorld. The same general statements are true to a large extent as 

 regards the species of Cyaniris. There is a single form on each continent 

 which extends across its entire width, but is not found in the high north. 

 As in Ileodes also, its inunediate relatives are found in greater abundance 

 in the Old AVorld than in the Xew ; but on the other hand the develop- 

 ment of varietal forms within the species is so greatly in excess in America, 

 that we must conclude it probable that its life on this continent has been 

 longer than on the Old. 



There remain only those species which occur within our district but 

 which belong more properly to high boreal regions. Among these we 

 have first a species of Oeneis (O. jutta) which is unipiestionably identical 

 on the two continents. Its distribution on this continent is probably 

 much more extensive than known, as it has l)cen found at widely distrib- 

 uted localities. The genus to which it belongs is a characteristically 

 alpine and arctic group, and is so widely develoi)ed on both continents 

 that here again it is extremely difficult to decide as to the probability of 

 its origin. Often living close l)esidc the ice, it has undoubtedly been a 

 com[>anion of the terminal moraine throughout the ages. One indication 

 might at first lead us to su})j)osc that the life of the genus may have been 

 the longer in Europe, 'i'his is the fact that in the Alps of ISwitzerland 

 there is a species very clearly distinct from any found in the north, while 

 on our own high mountain-tops O. semidea is considered by many writers 

 as identical with a species found in Labrador. J>ut both are waifs left 

 by the glacial epoch. Still, the bulk of genera to which the satyrids of 

 Europe are referred belong to the section Avith ribbed eggs, in which 

 Oeneis falls, while the contrary is true of the American forms. It v^ould 

 seem, therefore, as probable (though highly uncertain) that Oeneis origi- 

 nated in the Old AV'orld. 



All the other species, in the opinion of most critical entomologists, are 

 difif'erent from those of the Old World, l)ut in all cases they approach so 

 closely to them that many Avriters have considered them as identicid. 

 Polygonia faunus is a case in point. It has been considered as identical 

 with one of the forms of the variable Polygonia c-album of Europe ; but 

 the facts in the case would seem to show that, whereas the species of the 

 Old AV^orld are few and variable, those of the New are numerous and 

 closely allied, and at the same time frequently dimorphic or even polymor- 

 phic. The excess to which variability has extended in this country would 

 therefore seem to indicate this as its older abode. The oj)posite is proba- 

 bly true of Eugonia, represented in this country by a single species ; this 

 is considered l)y many as identical with Eugonia van-album of Europe, 



