MIMICRY 223 



mimic has found protection by other means than 

 mimicry ; it has as it were discarded mimicry in 

 favour of greater fertility, rapid flight, or even distinct 

 nauseous properties of its own ; its mimicry has be- 

 come arrested, the stern necessity for it no longer 

 existing. If the mimetic resemblance be harmless to 

 the species it will not be eliminated, and the species 

 may actually develop warning signals of its own. 

 Such an example seems to be afforded by the Chal- 

 cosiid moth, Pompelon subcyanea. This distasteful 

 moth mimics the male of the Euplceine Trepsichrois 

 mulciber, a black butterfly with a most brilliant metallic 

 blue sheen on the fore-wings, but the mimicry is very 

 imperfect because the moth is so much smaller than 

 the butterfly and has a different flight, so that no one 

 could mistake the two. The tip of the moth's 

 abdomen is bright scarlet, and this is a very con- 

 spicuous feature. Now it seems to me that this scarlet 

 tip is of value to the moth as a signal of still more 

 distasteful properties than the butterfly possesses ; the 

 moth, not content with advertising its unpalatability by 

 resembling an unpalatable butterfly, accentuates the 

 fact by developing an additional warning signal. This 

 is an extreme example, but the same reasoning applied 

 to other cases may explain much of the difficulty 

 which some find in regarding mimicry as efficient 

 when not quite perfect. That there is much which 

 cannot be explained by a facile application of the 

 theories of protective, warning, and mimetic colour and 

 form is very certain. Two instances may be noted 

 here. Nezara viridula is a little green Pentatomid 

 bug endowed with a positively nauseous odour ; it is 

 cryptically coloured, for green in Nature is a cryptic 



