612 



THE DESCENT OF MAN 



during incubation, and the young from being inexperienced, 

 had been rendered dull as a protection. But this view is not 

 supported by any evidence and is not probable; for we thus 

 m imagination expose during past times the females and the 

 young to danger, from which it has subsequently been neces- 

 sary to shield their modified descendants. We have, also, to 

 reduce, through a gradual process of selection, the females 

 and the young to almost exactly the same tints and mark- 

 ings, and to transmit them to the corresponding sex and 

 period of life. On the supposition that the females and 

 the young have partaken during each stage of the process 

 of modification of a tendency to be as brightly colored as 

 the males, it is also a somewhat strange fact that the females 

 Jiave never been rendered dull colored without the young 

 participating in the same change; for there are no instances, 

 as far as I can discover, of species with the females dull and 

 the young bright-colored. A partial exception, however, is 

 offered by the young of certain woodpeckers, for they have 

 "the whole upper part of the head tinged with red," which 

 afterward either decreases into a mere circular red line in- 

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

 females." 



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, oc- 

 curring 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 appeared, 

 have been from the" first transmitted only to the adult male 

 offspring. Any variations in brightness occurring in the 

 females or in the young would have been of no -service to 

 them, and would not have been selected; and, moreover, if 

 dangerous, would have been eliminated. Thus the females 

 and the young will either have been left unmodified, or (as 



" Audubon, "Omith. Biography," toI. i. p. 193. Macgillivray, "Hist. 

 British Birds," vol. lii. p. 85 See, also, the case before given of Indopicus 

 carlotta. 



