304 COLOUR IN NATURE chap. 



purpose. Another example of a similar elaboration 

 of protective resemblance may be also quoted from 

 Mr. Poulton's pages. The insect in this case was 

 found by Mr. W. L. Sclater in Tropical America. In 

 the place where it was found the leaf-cutting ants are 

 extremely numerous, and are constantly seen carrying 

 pieces of leaves " about the size of a sixpence held 

 vertically in the jaws." The insect found by Mr. 

 Sclater, though not an ant, resembled one ; and, 

 moreover, had an anterior, thin, flat expansion which 

 imitated the leaf carried by the ants, so that, as a 

 whole, in Mr. Poulton's words, the insect " mimicked 

 the ant, together with its leafy burden " {ibid. pp. 

 252, 253). Now, as it is only the homeward-bound 

 ants which carry pieces of leaves, it seems in 

 this case also that the protective resemblance is 

 unnecessarily laborious ; something less might surely 

 have served. 



Apart from this, however, the examples show how 

 some naturalists attack the problems of colour. It 

 is unnecessary here to go into further detail as to the 

 various applications of the theory ; most of these have 

 now become completely popularised. 



2. Mr. Wallace's Theory. — We shall next pass on 

 to consider the modification of this theory which is 

 supported by Mr. A. R. Wallace. Mr. Wallace, in his 

 book on Darwinism, expresses his general belief in 

 the theory of colour production implicit in such terms 

 as Mimicry, Warning Coloration, etc., and dissents 

 only from the theory of the origin of the bright 

 colours of males by Sexual Selection. In point of 

 fact, however, his dissent in reality carries him further 

 than this, and to some extent at least shakes the 



