II.] IXCIPIENT STRUCTURES. 37 



for the accuracy of the following details. These butterflies 

 frequent dry forests, and fly very swiftly. They were 

 seen to settle on a flower or a green leaf, but were many 

 times lost sight of in a bush or tree of dead leaves. On 

 such occasions they were generally searched for in vain, for 

 while gazing intently at the very spot where one had dis- 

 appeared, it would often suddenly dart out, and again 

 vanish twenty or fifty yards further on. On one or two 

 occasions the insect was detected reposing, and it could 

 then be seen how completely it assimilates itself to the 

 surrounding leaves. It sits on a nearly upright twig, the 

 wings fitting closely back to back, concealing the antennae 

 arid head, which are drawn up between their bases. The 

 little tails of the hind wing touch the branch, and form a 

 perfect stalk to the leaf, which is supported in its place by 

 .the claws of the middle pair of feet, which are slender and 

 inconspicuous. The irregular outline of the wings gives 

 exactly the perspective effect of a shrivelled leaf. We thus 

 have size, colour, form, markings, and habits, all combining 

 together to produce a disguise which may be said to be 

 absolutely perfect ; and the protection which it affords is 

 sufficiently indicated by the abundance of the individuals 

 that possess it." 



Beetles also imitate bees and wasps, as do some Lepi- 

 doptera; and objects the most bizarre and unexpected are 

 simulated, such as dung and drops of dew. Certain insects, 

 called bamboo and walking-stick insects, have a most 

 remarkable resemblance to pieces of bamboo, to twigs and 

 branches. Of these latter insects Mr. Wallace says : 1 

 " Some of these are a foot long and as thick as one's finger, 

 and their whole colouring, form, rugosity, and the arrange- 



1 Loc. cit. p. 64. 



