282 Colour and the Struggle for Infe 
enthusiasm at the brilliancy of the hypothesis and its caution in 
acceptance without full confirmation : 
“Bates was quite right; you are the man to apply to in a 
difficulty. I never heard anything more ingenious than your 
suggestion, and I hope you may be able to prove it true. That is 
a splendid fact about the white moths!; it warms one’s very blood to 
see a theory thus almost proved to be true.” 
Two years later the hypothesis was proved to hold for caterpillars 
of many kinds by J. Jenner Weir and A. G. Butler, whose observa- 
tions have since been abundantly confirmed by many naturalists. 
Darwin wrote to Weir, May 13, 1869: “ Your verification of Wallace’s 
suggestion seems to me to amount to quite a discovery *.” 
Recognition or Episematic Characters. 
This principle does not appear to have been in any way foreseen 
by Darwin, although he draws special attention to several elements 
of pattern which would now be interpreted by many naturalists as 
episemes. He believed that the markings in question interfered with 
the cryptic effect, and came to the conclusion that, even when 
common to both sexes, they “are the result of sexual selection 
primarily applied to the male’.” The most familiar of all recognition 
characters was carefully explained by him, although here too ex- 
plained as an ornamental feature now equally transmitted to both 
sexes: “The hare on her form is a familiar instance of concealment 
through colour; yet this principle partly fails in a closely-allied 
species, the rabbit, for when running to its burrow, it is made 
conspicuous to the sportsman, and no doubt to all beasts of prey, by 
its upturned white tail‘*.” 
The analogous episematic use of the bright colours of flowers 
to attract insects for effecting cross-fertilisation and of fruits to 
attract vertebrates for effecting dispersal is very clearly explained 
in the Origin’. 
It is not, at this point, necessary to treat sematic characters at 
any greater length. They will form the subject of a large part of the 
following section, where the models of Batesian (Pseudaposematic) 
mimicry are considered as well as the Miillerian (Synaposematic) 
combinations of Warning Colours. 
1 A single white moth which was rejected by young turkeys, while other moths were 
greedily devoured: Natural Selection, 1875, p. 78. 
4 More Letters, u. p. 71 (footnote). 3 Descent of Man, p. 544. 
+ Descent of Man, p. 542. 
5 Ed. 1872, p.161. For a good example of Darwin’s caution in dealing with exceptions 
see the allusion to brightly coloured fruit in More Letters, 1. p. 348. 
