[21] [Eng. ed. Dimorphism of this kind has since been made known: the North American _Limenitis Artemis_ and _L. Proserpina_ are not two species, as was formerly believed, but only one. Edwards bred both forms from eggs of _Proserpina_. Both are single-brooded, and both have males and females. The two forms fly together, but _L. Artemis_ is much more widely distributed, and more abundant than _L. Proserpina_. See “Butterflies of North America,” vol. ii.] [22] [Eng. ed. Edwards has since proved experimentally that by the application of ice a large proportion of the pupæ do indeed give rise to the var. _Telamonides_. He bred from eggs of _Telamonides_ 122 pupæ, which, under natural conditions, would nearly all have given the var. _Marcellus_. After two months’ exposure to the low temperature there emerged from August 24th to October 16th, fifty butterflies, viz. twenty-two _Telamonides_, one intermediate form between _Telamonides_ and _Walshii_, eight intermediate forms between _Telamonides_ and _Marcellus_ more nearly related to the former, six intermediate forms between _Telamonides_ and _Marcellus_, but more closely resembling the latter, and thirteen _Marcellus_. Through various mishaps the action of the ice was not complete and equal. See the “Canadian Entomologist,” 1875, p. 228. In the newly discovered case of _Phyciodes Tharos_ also, Edwards has succeeded in causing the brood from the winter form to revert, by the application of ice to this same form. See Appendix II. for a _résumé_ of Edwards’ experiments upon both _Papilio Ajax_ and _Phyciodes Tharos_. R.M.] [23] Thus from eggs of _Walshii_, laid on April 10th, Edwards obtained, after a pupal period of fourteen days, from the 1st to the 6th of June, fifty-eight butterflies of the form _Marcellus_, one of _Walshii_, and one of _Telamonides_. [24] [The word ‘Amixie,’ from the Greek ἀμιξία, was first adopted by the author to express the idea of the prevention of crossing by isolation in his essay “Über den Einfluss der Isolirung auf die Artbildung,” Leipzig, 1872, p. 49. R.M.] [25] [Eng. ed. In 1844, Boisduval maintained this relationship of the two forms. See Speyer’s “Geographische Verbreit. d. Schmetterl.,” i. p. 455.] [26] According to a written communication from Dr. Staudinger, the female _Bryoniæ_ from Lapland are never so dusky as is commonly the case in the Alps, but they often have, on the other hand, a yellow instead of a white ground-colour. In the Alps, yellow specimens are not uncommon, and in the Jura are even the rule. [27] [According to W. F. Kirby (Syn. Cat. Diurn. Lepidop.), the species is almost cosmopolitan, occurring, as well as throughout Europe, in Northern India (var. _Timeus_), Shanghai (var. _Chinensis_), Abyssinia (var. _Pseudophlæas_), Massachusetts (var. _Americana_), and California (var. _Hypophlæas_). In a long series from Northern India, in my own collection, all the specimens are extremely dark, the males being almost black. R.M.]