LEAF AND TENDRIL 



counter-cheeks, by some species being prolific and 

 other species less so, by the development of assimi- 

 lative colors by one kind, and of showy colors by 

 another, by slow but ceaseless modifications and 

 adaptations. It is a problem of many and complex 

 factors, in which, no doubt, color plays its part, 

 but I believe this part is a minor one. 



Note. — Since writing the above essay I have read Geddes 

 and Thomson on " The Evolution of Sex," and find that these in- 

 vestigators have anticipated my main idea in regard to the high 

 coloration and ornamentation of male birds, namely that these 

 things inhere in the male principle, or are "natural to maleness." 

 The males put on more beauty than females "because they 

 are males, and not primarily for any other reason whatever." 

 " Bright coloring or rich pigmentation is more characteristic of 

 the male than of the female constitution." " Males are stronger, 

 handsomer, or more emotional simply because they are males, 

 — i. e., of more active physiological habit than their mates." 

 The males tend to Uve at a loss, and are relatively more kata- 

 bolic; the females, on the other hand, tend to live at a profit, 

 and are relatively more anabolic. 



" Brilliancy of color, exuberance of hair and feathers, activity 

 of scent-glands, and even the development of weapons, cannot 

 be satisfactorily explained by sexual selection alone, for this is 

 merely a secondary factor. In origin and continued develop- 

 ment they are outcrops of a male as opposed to a female con- 

 stitution." 



