Chap. XVI.] THE YOUXG LIKE THE ADULT MALES. 191 



the adults of Loth sexes, or quite disappears in the adult 

 females. 12 



Finally, with respect to our present class of cases, the 

 most probable view appears to be, that successive varia- 

 tions in brightness or in other ornamental characters, 

 occurring in the males at a rather late period of life have, 

 alone been preserved ; and that most or all of these varia- 

 tions, owing to the late period of life at which they ap- 

 peared, have been from the first transmitted only to the 

 adult male offspring. Any variations in brightness which 

 occurred in the females or in the young would have been 

 of no service to them, and would not have been selected; 

 moreover, if dangerous, would have been eliminated. Thus 

 the females and the young will either have been left un- 

 modified, or, and this has much more commonly occurred, 

 will have been partially modified, by receiving, through 

 transference from the males, some of the successive varia- 

 tions. Both sexes have perhaps been directly acted on 

 by the conditions of life to which they have long been ex- 

 posed ; but the females, from not being otherwise much 

 modified, will best exhibit any such effects. These changes 

 and all others will have been kept uniform by the free in- 

 tercrossing of many individuals. In some cases, especially* 

 with ground-birds, the females and the young may possi- 

 bly have been modified, independently of the males, for 

 the sake of protection, so as to have acquired the same 

 dull-colored plumage. 



Class II. Whe?i the adult female is more conspicuous . 

 than the adult male, the young of both sexes in their first 

 plumage resemble the adult male. — This class is exactly the 

 reverse of the last, for the females are here more brightly 



12 Audubon, 'Ornith. Biography,' vol. i. p. 193. Macgillivray, 'Hist. 

 Brit. Birds,' vol. iii. p. 85. See also the case before given of Indopicus 

 carlolta. 



