Page:The Zoologist, 4th series, vol 3 (1899).djvu/337

Rh among insects and other living creatures which we seek in vain to explain by observed attack, and consequently cannot prove the present need of protection. These disguises are often like remains of old earthworks which we find on our peaceful downs; reminiscences of past struggles, records that such did once exist. And thus the suggestion is forced upon us that much present mimicry in nature is obsolete, more to be studied and explained by a zoological archæologist than by an outdoor observer, and accounts for the frequent remarks made from time to time to the writer by candid and competent naturalists abroad, that so much convincing theory at home receives little support when nature is cross-examined in her tropical and sub-tropical fastnesses.

In a book written by a popular writer, the late Prof. Henry Drummond, and which must have been read largely by the general public, for before us is the fourth edition of 'Tropical Africa,' which is described as "completing twenty-fifth thousand," there is a chapter devoted to "Mimicry; the ways of African insects." "Protective resemblance" would perhaps have been a more applicable title to the phenomena considered than "mimicry," which the author defines as "imposture in nature." But the peculiarity in this chapter is that the author, after agreeing in the fullest manner with the usual conception of the term "mimicry," as held by most biologists, and stating that "mimicry depends on resemblances between an animal and some other object in its environment of which it is a practical gain to the creature to be a more or less accurate copy," appears to altogether explain away that conclusion by the subsequent remark that, "while in some animals the disguises tend to become more and more perfect, the faculties for penetrating them in other animals must continually increase