Page:The Zoologist, 4th series, vol 3 (1899).djvu/559



To revert to "active mimicry," and to render our signification of the term as clear as possible, we will first adduce an instance given by that competent lepidopterist, Georg Semper:—"During the last ten years the well-known white-leaved variety of Acer negundo has been largely planted in gardens in Hamburg, and since this the common White Cabbage Butterfly has accustomed itself to settle by preference on this shrub. It is then extremely difficult to distinguish the butterflies as they sit on the leaves, their yellowish colour being lost in that of the leaves." Had Hamburg been a locality in some terra incognita, and visited by a travelling naturalist of observing faculties, who can doubt—and why should surprise be felt under the circumstances—that this observation would have appeared, and been recorded, as an Zool. 4th ser. vol. III., December, 1899.