214 



CALIFORNIA ACADEMY OF SCIENCES. 



Male like female. | ^- ^'°""" ^'^^ ^'^"" <^^')- 



I 2. Younc' like some ancestral stage of the adult (III) 



Resemblance of 

 sexes differs with 

 the seasons; or 

 both sexes may 

 vary with the 

 seasons (V). 



Male like female. 



f 3. Young like winter plumage 



of adult. 

 ) 4. Young differ from adults at 

 I any season, or intermediate 

 I between summer and winter 

 L plumage of latter. 



Male in breeding 



plumage differs 



from female. 

 Male unlike female 



in both plumages 



f Female more conspicuoiTslj' colored 

 male (II). 



!S I. 



5. Young with peculiar first 

 plumage. 



Young like female in win- 

 ter. 



young like 



6. 



Male unlike fe- 

 male. 



Male more conspic- 

 uously colored. 



7. Young like adult female (I). 



8. Young with peculiar first 

 plumage (VII). 



9. Yoiing male more or less like 

 adult male; young female like 

 adult female (VI). 



10. Young male unlike adult of 

 either sex; yoiiug female like 

 adult female (VIII). 



When the plumage of the male and female is the 

 same there is generally no variation with seasons, but 

 among some forms, especially some of the water birds 

 and waders, a bright plumage is assumed during the 

 breeding season by both sexes, corresponding to the 

 male plumage of species which are sexually dissimilar, 

 while the dull plumage of winter is analogous to the 

 ordinary dress of the female among forms sexually dif- 

 ferent in colors. The most complete stage of transmis- 

 sion of peculiar characters is (1) that in which the 

 species has but one phase of plumage, at all times of its 

 life, and in both sexes. The following list of species 

 and genera belonging to this class is based upon an ex- 

 amination of specimens in the National Museum. It 

 makes no pretense of being complete, but will serve to 

 indicate representative forms. An asterisk indicates 



