58 



TJie Study of Animal Life 



PART I 



The constant conditions of mimicry are clearly and tersely 

 summed up by Wallace. They are : — 



1. That the imitative species occur in the same area, 

 and occupy the very same station, as the imitated. 



2. That the imitators are always the more defenceless. 



3. That the imitators are always less numerous in 

 individuals. 



4. That the imitators differ from the bulk of their 

 allies. 



Fig. 10. — Humming-bird moth {^Mncroglossa titan'}, and humming-bird 

 {LoJ>honiis GoiiUiii). (From Bates.) 



5. That the imitation, however minute, is external and 

 visible only, never extending to internal characters or to 

 such as do not affect the external appearance. 



Many inedible butterflies are mimicked by others quite 

 different. Many longicorn beetles exactly mimic wasps, 

 bees, or ants. The tiger -beetles are mimicked by more 

 harmless insects ; the common drone-fly {Eristalis) is like 

 a bee ; spiders are sometimes ant-like. Mr. Bates relates 

 that he repeatedly shot humming-bird moths in mistake for 

 humming-birds. Among Vertebrates genuine mimicry is 

 rare, but it is well known that some harmless snakes mimic 



