THE CANADIAN ENTOMOLOGIST. 91 



Stage which it now possesses."* It appears, then, that while some genera 

 are extinct, others are represented by modern genera very near them, 

 and two belong to genera in use to-day. But the families and sub-families, 

 even to the aberrant Libythea, were as sharply defined as they are to-day. 

 Every family recognized by Mr. Scudder is represented, except the 

 Lyc{«nidrt3, but their absence is accounted for by reason of " their ex- 

 ceedingly delicate structure and small size ; " and it is added, " but there 

 are intimations of the presence of some of their caterpillars in amber," 

 which is a product of the tertiaries. And there is not a species about 

 which there is a doubt as to what family and sub-family it belongs. The 

 neuration of wings, the legs, palpi and antennae were just as now. It is 

 proved, therefore, so fer as there is any evidence at all, that since the 

 Eocene, the families and sub-families of butterflies have not changed an 

 iota. Mr. Scudder is happy in the poetical quotations prefixed to his 

 chapters, and he might have put over the one on fossil butterflies, '' Such 

 as creation's dawn beheld, we see thee now." New species have been 

 evolved and new genera, but no new families. Of sub-families we 

 miss f/iaf of the Papilionince, whose absence, considering their size and 

 stout texture of wing, and especially if they were among the first to evolve 

 from the " common stfjck,'' and, therefore, were always present when any 

 butterfly at all was flying, is remarkable. If they were really the latest to 

 develop, we can understand their absence. 



From the beginning of the tertiaries there was a steady advance in 

 the grade of mammals and birds. The supposed ancestors of existing 

 species in these classes are found there, new types manifesting themselves 

 as the period progressed. The families are not those of to-day, but one 

 has developed into many. This very week there is going the rounds of 

 the papers a description of the mammal Phenacodus-primevus, an animal 

 both herbivorous and carnivorous, from the Eocene of Dacotah, which 

 Dr. Cope considers the ancestor of the elephant and giraffe, the plan- 

 tigrades, the carnivora and hoofed animals of to-day. But, in the butter- 

 flies, there is no evidence of any change whatever. 



The hypothesis, advanced by Mr. Scudder, calls for a duration of time 

 which is inadmissable. It is a problem in the Rule of Three ; if butter- 



* If, as I have supposed, the atrophy of legs originated suddenly and to full extent 

 in the type, and was perpetuated by descent, we can understand why it appears on the 

 earliest horizon ; otherwise, not. But if it was a malformation from the first, no degree 

 of perpetuation would change its character. 



