110 MIMICRY, AND OTHER PROTECTIVE 



influence all groups related to each other in an equal 

 degree. Again, the general fact that those species 

 which mimic others are rare, while those which are 

 imitated are abundant, is in no way explained by either 

 of these theories, any more than is the frequent occur- 

 rence of some palpable mode of protection in the 

 imitated species. " Reversion to an ancestral type " 

 no way explains why the imitator and the imitated 

 always inhabit the very same district, whereas allied 

 forms of every degree of nearness and remoteness 

 generally inhabit different countries, and often dif- 

 ferent quarters of the globe; and neither it, nor 

 " similar conditions," will account for the likeness be- 

 tween species of distinct groups being superficial only 

 a disguise, not a true resemblance ; for the imitation 

 of bark, of leaves, of sticks, of dung ; for the resem- 

 blance between species in different orders, and even 

 different classes and sub-kingdoms ; and finally, for the 

 graduated series of the phenomena, beginning with a 

 general harmony and adaptation of tint in autumn and 

 winter moths and in arctic and desert animals, and 

 ending with those complete cases of detailed mimicry 

 which not only deceive predacious animals, but puzzle 

 the most experienced insect collectors and the most 

 learned entomologists. 



Mimicry by Female Insects only. 



But there is yet another series of phenomena con- 

 nected with this subject, which considerably strengthens 

 the view here adopted, while it seems quite incompa- 



