172 



three forms well-defined going to make up the present American rep- 

 resentative of the ancient species. There is resemblance between 

 Chrysotheme and one of the forms of Eurytheme, but not more than there 

 is between Philodice and Eurytheme^ save in the single character of 

 color. If Chrysotheme on a large scale could be introduced to cay to 

 America, it would breed true to its own type, and be a constant spe ies 

 just as it is in Europe. It would be .iges before it would vary largely 

 and could part into defined forms, and these might vary much from the 

 forms under which we know EurytJieme. The only rational explana- 

 tion is that of community of origin, and in both continents modification 

 has taken place, resulting in well-separated species. Each is true to 

 its own type, has marked peculiarities, and is permanent; and there- 

 fore is a species; and the two are species.* 



Carrying this explanation a step farther : not only have those two 

 orange species sprung from one ancient species, but the three others 

 before named have come from the same source. f Of these, Eri- 

 phyle has possession of the Pacific Coast towards the Rocky 

 Mountains, and at least as far south as the United States bound- 

 ary line; Hagetiii occupies the Rocky Mountain region from 

 southern Colorado well into British America, and to the east as far as 

 the desert country; Philodice inhabits the Atlantic and Gulf States, 

 part of the Mississippi Valley, and part of Canada, but there is no evi- 

 dence that it has yet crossed the desert belt to the west, or anywhere 



*Dr. Staudinger, in his Cat. 1871, gives the location of C/nysotheme as {o\\o\\-s: East- 

 ern Middle Europe, Asia Minor, Armenia, Middle and Eastern Siberia. I wrote Mr. 

 A. G. Butler for any information he could give me. He says, " I strongly suspect it 

 to be a strictly European species. The B. Museum contains examples from Germany 

 only." I also vk^rote Dr. Staudinger, and he replies, 8th Oct., 1883; " In all the col- 

 lections I have received in the last ten years from Central and North Asia tke7-e never 

 ivas one Chrysothetne. I have only one specimen from East Siberia in my collection, 

 but this was in the large Hopffer collection which I bought. / have received Chryso- 

 theme only from Southeast Europe. I never met or received it from Asia Minor. 

 Chrysotheme varies, and the first generation is always somewhat different from tie 

 second. I received from Lapland some C. Necla, very near to Chrysotheme, and it 

 may be the former is the northern form of that species. Also your Keewaydin is hard- 

 ly to be distinguished from Chrysotheme, and 1 have also from your very variable N. 

 Am. species, Eutvthemc, specimens which are hardly to be distinguished. Perhaps 

 all are from the same species, not connected by Siberia and Japan, Init by the Polar re- 

 gions, from the titne when America and Europe were connected by land." The last sug- 

 gestion is in accordance with what I have written in this paper, and is the proper one. 

 I notice that neither Staudinger nor Zeller claim identity between Chrysotheme and 

 Keeivaydin. Staudinger says the former can " hardly be distinguished" from the lat- 

 ter, implying a difference. Zeller says, " I myself have taken a m&Xe. {Chrysotheme) at 

 Vienna with so little orange on the inner half of the wing that a North American could 

 scarcely distinguish it among a number of male Keewaydin," and adds: " If Keeway- 

 din and Chrysotheme are really the same species, we may well say that species vary 

 much more in North America than in Europe." Ent. Zeit, 1874. 



f It is my opinion that most, if not all, of the present species of Colias, in N. Am., 

 must be more closely related to Eurytheme than Chrysotheme can be, having probably 

 diverged in successive steps from the glacial form since the parting of the American 

 and European branches. Any resemblance between Chrysotheme and Eurytiieme now 

 would be owing to both having retained some features of the ancient form. All the 

 yellow species of Colias seem to have a tendency to orange spots, and I infer that the 

 ancestral species was orange. 



