Note 21 — Part I. ON THE SEASONAL DIMORPHISM OF BUTTERFLIES.

[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.]