Protective Resemblance 277 



The cryptic resemblances of animals impressed Darwin and 

 Wallace in very different degrees, probably in part due to the fact 

 that Wallace's tropical experiences were so largely derived from the 

 insect world, in part to the importance assigned by Darwin to Sexual 

 Selection "a subject which had always greatly interested me," as he 

 says in his Autobiography 1 . There is no reference to Cryptic 

 Resemblance in Darwin's section of the Joint Essay, although he 

 gives an excellent short account of Sexual Selection (see p. 295). 

 Wallace's section on the other hand contains the following statement : 

 "Even the peculiar colours of many animals, especially insects, so 

 closely resembling the soil or the leaves or the trunks on which they 

 habitually reside, are explained on the same principle ; for though in 

 the course of ages varieties of many tints may have occurred, yet 

 those races having colours best adapted to concealment from their 

 enemies would inevitably survive the longest 2 ." 



It would occupy too much space to attempt any discussion of 

 the difference between the views of these two naturalists, but it 

 is clear that Darwin, although fully believing in the efficiency of 

 protective resemblance and replying to St George Mivart's con- 

 tention that Natural Selection was incompetent to produce it 3 , never 

 entirely agreed with Wallace's estimate of its importance. Thus the 

 following extract from a letter to Sir Joseph Hooker, May 21, 1868, 

 refers to Wallace : " I find I must (and I always distrust myself when 

 I differ from him) separate rather widely from him all about birds' 

 nests and protection ; he is riding that hobby to death 4 ." It is clear 

 from the account given in The Descent of Man b , that the divergence 

 was due to the fact that Darwin ascribed more importance to Sexual 

 Selection than did Wallace, and Wallace more importance to Pro- 

 tective Resemblance than Darwin. Thus Darwin wrote to Wallace, 

 Oct. 12 and 13, 1867: "By the way, I cannot but think that you push 

 protection too far in some cases, as with the stripes on the tiger 6 ." 

 Here too Darwin was preferring the explanation offered by Sexual 

 Selection 7 , a preference which, considering the relation of the colouring 

 of the lion and tiger to their respective environments, few naturalists 

 will be found to share. It is also shown on p. 280 that Darwin con- 

 templated the possibility of cryptic colours such as those of Patagonian 

 animals being due to sexual selection influenced by the aspect of 

 surrounding nature. 



1 Life and Letters, Vol. i. p. 94. 



2 Journ. Proc. Linn. Soe. Vol. in. 1859, p. 61. The italics are Wallace's. 



3 Origin (6th edit.) London, 1872, pp. 181, 182; see also p. 66. 

 * More Letters, i. p. 804. 



5 London, 1874, pp. 452 — 458. See also Life and Letters, m. pp. 123—125, and More 

 Letters, n. pp. 59—63, 72—74, 76—78, 84— 90, 92, 93. 



6 More Letters, i. p. 283. 7 Descent of Man (2nd edit.) 1874, pp. 545, 546. 



