KViMPlIALlNAK: THE (HOM'S I'()LV(;()XI A. 315 



vous, iiTegular Hight, so that (Jooftroy nanu'd the coiuinon European 

 species Robert le l)i<ihle ; they are fond of" the juices of fruit and the saj> 

 of trees, and arc usually found by the roadside or on sunny spots in the 

 vicinity of woods, alighting almost invariably on horizontal surfaces, in 

 souK'wliat striking distinction from Eugonia and Eiivanessa, which are fond 

 of pitching erect on trunks of trees. 



The fondness of the butterflies for the vicinity of forests makes it probable 

 that they hibernate in the woods. Mr. Goossens in beating small trees 

 over his open umbrella in the cold days of November, near Paris, twice 

 brought down specimens of the European P. c-album, which fell with 

 closed wings ; apparently they must have chosen the imder side of 

 branches for hibernation, as has been seen in the case of other Vanessidi. 



Most of our Xew England species, and some at least of the others, are 

 dimorphic to a greater or less extent, the two forms generally differing in 

 the extent or depth of the darker markings of the upper surface, and the 

 stronger or weaker contrasts between the colors of the under surface. The 

 dimor[)hic species, so far as known, are double brooded, and the others (at 

 least in New England, i. e., faunus and gracilis) single bi'ooded. The 

 dimorphism is to a large extent — almost exclusively — seasonal, the first 

 brood of butterflies being the darker, the autumn brood the lighter. The 

 European c-album is double brooded, and varies so much that it should be 

 deemed polymorphic, but no proper investigation of the relation of the dif- 

 ferent forms to eacii other has ever been made. Notwithstanding which, 

 European entomologists of repute consider several of our species (which 

 have been shown to difler unmistakably in structural features), to be 

 identical with their own polymorphic form — a position which is utterly 

 untenable. Mr. Edwards has discussed this point very fully in his Butter- 

 flies of North America. Mr. Mead su<?oests that the varieties of the 

 European c-album are "nascent species,'' — a stage which the American 

 species, as older forms, have already past. 



The e^^ is nearly spherical, but somewliat barrel shaped, and furnished 

 witli ten compressed, longitudinal ribs, which, on the upper half, greatly 

 increase in height. The head of the voung larva is smooth and the body 

 furnished Avith six rows of minute warts, each emitting a long tapering 

 hair. Tn the nuiture larva the head is crowned by a ])air of long, stout, 

 aculiferoiis spines ; and the body bears seven longitudinal rows of mammi- 

 form elevations, each surmounted by a sjiine beset with whoi'ls of delicate 

 bristles. The chrvsalids arc angular and tubercidatcd, the ocellar promi- 

 nences more or less conical and pointed, and the dorsum of the tliorax 

 produced like a very strongly compressed, very prominent, subquadrate 

 keel, sometimes sliaped like a Koman nose. 



