236 ENTOMOLOGY 



lution has been attributed by Darwin and many of his follow- 

 ers to sexual selection a highly debatable subject. Among 

 insects, however, no such phenomenon has been found ; when- 

 ever 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 of 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 re- 

 stricted to the preservation and accumulation of such advan- 

 tageous variations as may arise, from whatever causes. As 

 Poulton says, the vast body of facts, utterly meaningless under 

 any other theory, become at once intelligible as they fall har- 

 moniously into place under the principle of natural selection, 

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



