MIMICRY 227 



opinion it is so because there is something inherent in 

 Phasmid protoplasm which has caused variation to pro- 

 ceed along the green and pink "rails," and prevents it 

 from going along blue and yellow "rails." So too with 

 the black and white or yellow Pierince that type of 

 coloration is inherent in Pierine protoplasm. 



A student of mimicry cannot fail to be struck with 

 the fact that mimetic resemblances are due to a simu- 

 lation of the model's characters and not to a direct 

 imitation of them. A fly mimicking a wasp does not 

 develop a second pair of wings to imitate the wasp's 

 wings, but the wings of the fly may be so formed 

 and so veined or grooved that they appear like the 

 four wings of the wasp. Let us note one or two 

 more instances of this from Borneo. A beetle of the 

 distasteful family Endomychidce and belonging to the 

 genus Spathomeles has a strong stout spine on each 

 wing-case, and this character of spiny wing-cases 

 or elytra is common to all the Amphisterni. This 

 particular Spathomeles is closely mimicked by a 

 Longicorn beetle Zelota spathomelina ; the mimic 

 is coloured like its model, and from each elytron 

 springs what appears to be a spine, but on close 

 examination is seen to be nothing but a finely pointed 

 tuft of hairs. In other words, the spine of the model 

 is simulated by the hair-tuft of the mimic. If natural 

 selection is all-powerful, if it can guide variations into 

 any and every direction, why has it not called into 

 being a spine on the elytron of the Longicorn ? 

 Spinosity of the elytra is unknown amongst Longicorns, 

 pubescence is common, and natural selection must 

 use the material to hand and make the best of that. 

 To take another instance : there occur in Borneo 



