298 THE LOWER AMAZONS. Chap. VIT. 



genera. Thus, on the Upper Amazons, another totally 

 distinct kind of Agrias mimicks still more closely another 

 Callithea ; both insects being peculiar to the district 

 where they are found flying together. Resemblances 

 of this nature are very numerous in the insect world. 

 I was much struck with them in the course of my 

 travels, especially when, on removing from one district 

 to another, local varieties of certain species were found 

 accompanied by local varieties of the species which 

 counterfeited them in the former locality, under a dress 

 changed to correspond with the altered liveries of the 

 species they mimicked. One cannot help concluding 

 these imitations to be intentional, and that nature has 

 some motive in their production. In many cases, the 

 reason of the imitation is sufficiently plain. For instance, 

 when a fly or parasitic bee has a deceptive resem- 

 blance to the species of working bee, in whose nest it 

 deposits the egg it has otherwise no means of provid- 

 ing for, or when a leaping-spider, as it crouches in the 

 axil of a leaf waiting for its prey, presents an exact 

 imitation of a flower-bud ; it is evident that the benefit 

 of the imitating species is the object had in view. 

 When, however, an insect mimicks another species of 

 its own order where predaceous or parasitic habits are 

 out of the question, it is not so easy to divine the precise 

 motive of the adaptation. We may be sure, never- 

 theless, that one of the two is assimilated in external 

 appearance to the other for some purpose useful, — per- 

 haps of Hfe and death importance — to the species. I 

 believe these imitations are of the same nature as those 

 in which an insect or lizard is coloured and marked 



