CHAPTER II 



MIMICRY — BATESIAN AND MtTLLERIAN 



Mimicry is a special branch of the study of adap- 

 tation. The term has sometimes been used loosely 

 to include cases where an animal, most frequently 

 an insect, bears a strong and often most remarkable 

 resemblance to some feature of its inanimate sur- 

 roundings. Many butterflies with wings closed are 

 wonderfully like dead leaves ; certain spiders when 

 at rest on a leaf look exactly like bird-droppings ; 

 "looper" caterpillars simulate small twigs ; the names 

 of the "stick-" and "leaf-" insects are in themselves 

 an indication of their appearance. Such cases as 

 these, in which the creature exhibits a resemblance to 

 some part of its natural surroundings, should be 

 classified as cases of "protective resemblance" in 

 contradistinction to mimicry proper. Striking ex- 

 amples of protective resemblance are abundant, and 

 though we possess little critical knowledge of the 

 acuity of perception in birds and other insect feeders 

 it is plausible to regard the resemblances as being 

 of definite advantage in the struggle for existence. 

 However, it is with mimicry and not with protec- 

 tive coloration in general that we are here directly 



