316 CALIFORNIA ACADEMY OF SCIENCES. 



The colors are to be accounted for almost wholly by the 

 effect of environment and general laws of pigment de- 

 velopment. It is a remarkable thing that two forms so 

 much alike in respect to coloration as these genera are, 

 should have no discriminative marks. It may be that 

 the similarity of coloration is due to a retrogressive coii- 

 vergance, this view being strengthened by the similarity 

 of the coloration of both genera to the young of Tachy- 

 cineta. 



FAMILY AMPELID.E. THE WAXWINGS, ETC. 

 GENUS AMPELIS. THE WAXWINGS. 



(2) Adult male like female; young like some ances- 

 tral stage of the adult. 



Prevailing colors, black, white, brown, vinaceous, 

 cinnamon, ashy, gray, yellow. 



I see no possible way of accounting for the beautiful 

 soft blended tints of these birds, except by sexual selec- 

 tion. The attainment of the goal of specialization by the 

 male has permitted the female to acquire the complete 

 plumage of the male, but the young still retains upon 

 the under parts the streaks of the ancestral bird. The 

 white wing markings so conspicuous in A. garrulus are 

 recognition marks, probably both directive and discrim- 

 inative in nature. The rufous under tail coverts of this 

 species as contrasted with the white of A. cedrorum, ap- 

 pear to be a discriminative mark. An interesting ex- 

 ample of correlation is to be found in the wax-like 

 appendages to the wing feathers, which are also occasion- 

 ally present, but in less pronounced degree, upon the 

 tail. This genus also affords an instance of red as the 

 correlative of yellow in the border of the tail, which is 

 yellow in North American species, but red in the Jap- 

 anese waxwing (A. japonicus). 



