[Footnote 65: _Proceedings of the Royal Society_, No. 243, 1886; _Transactions of the Royal Society_, vol. clxxviii. B. pp. 311-441.]
[Footnote 66: _A Naturalist's Wanderings in the Eastern Archipelago_, p. 460.]
[Footnote 67: _Trans. Phil. Soc._ (? _of S. Africa_), 1878, part iv, p. 27.]
[Footnote 68: _Proc. Zool. Soc._, 1862 p. 357.]
[Footnote 69: With reference to this general resemblance of insects to their environment the following remarks by Mr. Poulton are very instructive. He says: "Holding the larva of Sphinx ligustri in one hand and a twig of its food-plant in the other, the wonder we feel is, not at the resemblance but at the difference; we are surprised at the difficulty experienced in detecting so conspicuous an object. And yet the protection is very real, for the larvae will be passed over by those who are not accustomed to their appearance, although the searcher may be told of the presence of a large caterpillar. An experienced entomologist may also fail to find the larvae till after a considerable search. This is general protective resemblance, and it depends upon a general harmony between the appearance of the organism and its whole environment. It is impossible to understand the force of this protection for any larva, without seeing it on its food-plant and in an entirely normal condition. The artistic effect of green foliage is more complex than we often imagine; numberless modifications are wrought by varied lights and shadows upon colours which are in themselves far from uniform. In the larva of Papilio machaon the protection is very real when the larva is on the food-plant, and can hardly be appreciated at all when the two are apart." Numerous other examples are given in the chapter on "Mimicry and other Protective Resemblances among Animals," in my _Contributions to the Theory of Natural Selection_.]
[Footnote 70: _The Naturalist in Nicaragua_, p. 19.]
[Footnote 71: R. Meldola, in _Proc. Zool. Soc._, 1873, p. 155.]
[Footnote 72: _Nature_, vol. iii. p. 166.]
[Footnote 73: _Trans. Ent. Soc. Lond._, 1878, p. 185.]
[Footnote 74: _Ibid._ (_Proceedings_, p. xlii.)]
[Footnote 75: Wallace's _Malay Archipelago_, vol. i. p. 204 (fifth edition, p. 130), with figure.]
[Footnote 76: Moseley's _Notes by a Naturalist on the Challenger_.]
[Footnote 77: _Proceedings of the Boston Soc. of Nat. Hist._, vol. xiv. 1871.]
[Footnote 78: _Nature_, 1870, p. 376.]
[Footnote 79: _A Naturalist's Wanderings in the Eastern Archipelago_, p. 63.]
[Footnote 80: A beautiful drawing of this rare insect, Hymenopus bicornis (in the nymph or active pupa state), was kindly sent me by Mr. Wood-Mason, Curator of the Indian Museum at Calcutta. A species, very similar to it, inhabits Java, where it is said to resemble a pink orchid. Other Mantidae, of the genus Gongylus, have the anterior part of the thorax dilated and coloured either white, pink, or purple; and they so closely resemble flowers that, according to Mr. Wood-Mason, one of them, having a bright violet-blue prothoracic shield, was found in Pegu by a botanist, and was for a moment mistaken by him for a flower. See _Proc. Ent. Soc. Lond._, 1878, p. liii.]
[Footnote 81: C. Dixon, in Seebohm's _History of British Birds_, vol. ii. Introduction, p. xxvi. Many of the other examples here cited are taken from the same valuable work.]
[Footnote 82: See A.H.S. Lucas, in _Proceedings of Royal Society of Victoria_, 1887, p. 56.]
[Footnote 83: Professor Wm.H. Brewer of Yale College has shown that the white marks or the spots of domesticated animals are rarely symmetrical, but have a tendency to appear more frequently on the left side. This is the case with horses, cattle, dogs, and swine. Among wild animals the skunk varies considerably in the amount of white on the body, and this too was found to be usually greatest on the left side. A close examination of numerous striped or spotted species, as tigers, leopards, jaguars, zebras, etc., showed that the bilateral symmetry was not exact, although the general effect of the two sides was the same. This is precisely what we should expect if the symmetry is not the result of a general law of the organisation, but has been, in part at least, produced and preserved for the useful purpose of recognition by the animal's fellows of the same species, and especially by the sexes and the young. See _Proc. of the Am. Ass. for Advancement of Science_, vol. xxx. p. 246.]
[Footnote 84: _Descent of Man_, p. 542.]
[Footnote 85: It may be thought that such extremely conspicuous markings as those of the zebra would be a great danger in a country abounding with lions, leopards, and other beasts of prey; but it is not so. Zebras usually go in bands, and are so swift and wary that they are in little danger during the day. It is in the evening, or on moonlight nights, when they go to drink, that they are chiefly exposed to attack; and Mr. Francis Galton, who has studied these animals in their native haunts, assures me, that in twilight they are not at all conspicuous, the stripes of white and black so merging together into a gray tint that it is very difficult to see them at a little distance. We have here an admirable illustration of how a glaringly conspicuous style of marking for recognition may be so arranged as to become also protective at the time when protection is most needed; and we may also learn how impossible it is for us to decide on the inutility of any kind of coloration without a careful study of the habits of the species in its native country.]
[Footnote 86: The principle of colouring for recognition was, I believe, first stated in my article on "The Colours of Animals and Plants" in Macmillan's _Magazine_, and more fully in my volume on _Tropical Nature_. Subsequently Mrs. Barber gave a few examples under the head of "Indicative or Banner Colours," but she applied it to the distinctive colours of the males of birds, which I explain on another principle, though this may assist.]
[Footnote 87: Quoted by Darwin in _Descent of Man_, p. 317.]
[Footnote 88: In the _American Naturalist_ of March 1888, Mr. J.E. Todd has an article on "Directive Coloration in Animals," in which he recognises many of the cases here referred to, and suggests a few others, though I think he includes many forms of coloration--as "paleness of belly and inner side of legs"--which do not belong to this class.]
[Footnote 89: For numerous examples of this protective colouring of marine animals see Moseley's _Voyage of the Challenger_, and Dr. E.S. Morse in _Proc. of Bost. Soc. of Nat. Hist._, vol. xiv. 1871.]
[Footnote 90: See _Origin of Species_, p. 107.]
[Footnote 91: The "Geographical Variation of North American Squirrels," _Proc. Bost. Soc. of Nat. Hist._, 1874, p. 284; and _Mammals and Winter Birds of Florida_, pp. 233-241.]
