ADAPTIVE COLORATION 211 



Recognition Markings. Though these are apparently important 

 mong mammals and birds, as enabling individuals of the same species 

 uickly to recognize and follow one another, no special markings for 

 is purpose are known to occur among insects, not excepting the gre- 

 arious migrant species, such as Anosia plexippus and the Rocky 

 Mountain locust. 



Epigamic Colors. Among birds, frequently, the bright colors of 

 the male are displayed during courtship, and their evolution has been 

 attributed by Darwin and many of his followers to sexual selection a 

 highly debatable subject. Among insects, however, no such phenome- 

 non has been found; whenever the two sexes differ in coloration the 

 difference does not appear to facilitate the recognition of even one sex 

 by the other. 



Evolution of Adaptive Coloration. Natural selection is the only 

 theory of any consequence that explains the highly involved phenomena 

 oi adaptive coloration. Against such vague and unsupported theories 

 as the action of food, climate, laws of growth or sexual selection, natural 

 selection alone accounts for the multitudinous and intricate correlations 

 of color, pattern, form, attitude, movement, place, time, etc., that are 

 necessary to the development of a perfect case of protective resemblance 

 or mimicry. Natural selection cannot, of course, originate colors or any 

 other characters, its action being restricted to the preservation and 

 accumulation of such advantageous variations as may arise, from what- 

 ever causes. As Poulton says, the vast body of facts, utterly meaning- 

 less under any other theory, become at once intelligible as they fall 

 harmoniously into place under the principle of natural selection, to 

 which, indeed, they yield the finest kind of support. 



