My life : a record of events and opinions - Wallace-online.org

212 MY LIFEMany of these had appeared in little-known periodicals,and were now carefully revised, or partially rewritten,while two new ones were added. The longest article,occupying nearly a quarter of the volume, was onewhich I had written in 1865-6, but which was notpublished (in the Westminster Review) till July, 1867,and was entitled "Mimicry, and other ProtectiveResemblances among Animals." In this article Iendeavoured to give a general account of the wholesubject of protective resemblance, of which theory,what was termed by Bates "mimicry," is a verycurious special case. I called attention to the wideextent of the phenomenon, and showed that itpervades animal life from mammals to fishes andthrough every grade of the insect tribes. I pointedout that the whole series of phenomena depend uponthe great principle of the utility of every character,upon the need of protection or of concealment byalmost all animals, and upon the known fact that nocharacter is so variable as colour, and that thereforeconcealment has been most easily obtained by colourmodification.Two other articles which may be just mentionedare those entitled " A Theory of Birds' Nests " and"The Limits of Natural Selection applied to Man."In the first I pointed out the important relation thatexists between concealed nests and the bright coloursof female birds, leading to conclusions adverse toMr. Darwin's theory of colours and ornaments in themales being the result of female choice. In theother (the last in the volume) I apply Darwin'sprinciple of natural selection, acting solely by meansof " utilities," to show that certain physical modificationsand mental faculties in man could not havebeen acquired through the preservation of useful