150 ORGANIC EVOLUTION 



think of the brilliant colors of the male and the more modest 

 coloring of the female in the peacock, the common chickens 

 (Plates 12-15), the argus pheasant (Plate 24, A), the birds of 

 paradise, the oriole, cardinal, and bobolink (Plate 22), the 

 bluebird, American goldfinch, and the indigo-bird. Even the 

 robin and the common grackle, or blackbird, show brighter 

 colors in the male than in the female. The humming-birds 

 also are good illustrations (Plate 26). 



The brilliant bronze-green-and-blue neck of the males of 

 our common eastern tree lizards is an instance of sexual 

 coloration. Other finer examples could be mentioned 

 among tropical lizards. In many species of fish the males 

 are much brighter colored than the females, and they 

 display the brilliant colored parts of the body to full 

 advantage when approaching the females in the breeding 

 season. 



Greater brilliancy of color in the male than in the female 

 is a quite general rule among fishes, and it is important to 

 note that, in those cases in which the courting habits of 

 species with bright-colored males have been observed, the 

 male has the habit of displaying to the greatest advantage 

 his bright colors when he approaches the female. 



Not only do we find differences in color between the 

 sexes among the fishes ; we also find instances of differ- 

 ences in form, the males having certain ornamental append- 

 ages not seen in the females, or the fins of the males being 

 larger (Plate 32). 



See also Plates 84 and 85 for illustrations of differences 

 in coloration between the sexes in butterflies, moths, and 

 spiders. 



