546 THE DESCENT OF MAN. 



I will specify the few other cases known to me, in which 

 the female is more conspicuously colored than the male, 

 althougli nothing is known about the manner of incuba- 

 tion. With the carrion-hawk of the Falkland Islands 

 [Milvago leucurus) I was much surprised to find by dissec- 

 tion that the individuals, which had all their tints strongly 

 pronounced, with the cere and legs orange-colored, were the 

 adult females; Avhile those with duller plumage and gray 

 legs were the males or tlie young. In an Australian tree- 

 creeper [Climacteris erythrops) the female differs from the 

 male in "being adorned with beautiful, radiated, rufous 

 markings on the tliroat, the male having this part quite 

 plain." Lastly, in an Australian night-jar "the female 

 always exceeds the male in size and in the brilliance of 

 her tints; the males, on the otljer hand, have two white 

 spots on the primaries more conspicuous than in the 

 female."* 



We thus see that the cases in which female birds are 

 more conspicuously colored than the males, with the young 

 in their immature plumage resembling the adult males 

 instead of the adult females, as in the previous class, are 

 not numerous, though they are distributed in various 

 orders. The amount of difference, also, between the sexes 

 is incomparably less than that wliich frequently occurs in 

 the last class; so that the cause of the difference, whatever 

 it may have been, has here acted on the females either less 

 energetically or less persistently than on the males in the 

 last class. Mr. Wallace believes that the males have had 



* For the Milvago, see "Zoology of the Voyage of the 'Beagie': 

 Birds," 1841, p. 16. For the Climacteris and night-jar (Eurostopo- 

 dus), see Gould's " Hand-book to the Birds of Australia," vol. i, pp. 

 602, 97. The New Zealand shieldrake {Tadorna variegata) offers a 

 quite anomalous case; the head of the female is pure white, and her 

 back is redder than that of the male; the head of tflie male is of a 

 rich dark bronzed color, and his back is clothed with finely penciled 

 slate-colored feathers, so that altogether he may be considered as the 

 more beautiful of the two. He is larger and more pugnacious than 

 the female, and does not sit on the eggs. So that in all these respects 

 this species comes under our first class of cases; but Mr. Sclater 

 ("Proc. Zool. Soc," 1866, p. 150) was much surprised to observe 

 that the young of both sexes, when about three months old, resem- 

 bled in their dark heads and necks the adult males, instead of the 

 adult females; so that it would appear in this case that the females 

 have been modified, while the males and the young have retained 9, 

 former state of plumage. 



