Ch. XVI. THE YOUNG LIKE ADULTS OF SAME SEX. 221 



nut-brown colour with a golden-reel head, is the male, 

 whilst the other, which is elegantly variegated Avith 

 green and white with a metallic-green head, is the fe- 

 male. Now the yonng from the first resemble to a 

 certain extent the adnlts of the corresponding sex, the 

 resemblance gradually becomiug more and more com- 

 plete. 



In considering this last case, if as before we take the 

 plumage of the young as our guide, it would appear 

 that both sexes have been independently rendered 

 beautiful ; and not that the one sex has partially trans- 

 ferred its beauty to the other. The male apparently 

 has acquired his bright colours through sexual selec- 

 tion in the same manner as, for instance, the peacock or 

 pheasant in our first class of cases ; and the female in 

 the same manner as the female Khynchaea or Turnix 

 in our second class of cases. But there is much diffi- 

 culty in understanding how this could have been 

 effected at the same time with the two sexes of the 

 same s]3ecies. Mr. Salvin states, as we have seen in 

 the eighth chapter, that with certain humming-birds 

 the males greatly exceed in number the females, whilst 

 with other species inhabiting the same country the 

 females greatly exceed the males. If, then, we might 

 assume that during some former lengthened period the 

 males of the Juan Fernandez species had greatly ex- 

 ceeded the females in number, but that durinir another 

 lengthened period the females had greatly exceeded 

 the males, we could understand how the males at one 

 time, and the females at another time, might have been 

 rendered beautiful by tlie selection of the brighter- 

 coloured individuals of either sex ; both sexes transmit- 

 ting their characters to their young at a rather earlier 

 age than usual. Whether this is the true explanation I 



