594 THE DESCENT OF MAN 



sexes are so unlike that they might easily be mistaken for 



distinct species." 



The laws of inheritance can alone account for the follow- 

 ing cases, in which the female acquires, late in life, certain 

 characters proper to the male, and ultimately comes to re- 

 semble him more or less completely. Here protection can 

 hardly have come into play. Mr. Blyth informs me that 

 the females of Oriolus melanocephalus and of some allied 

 species, when sufficiently mature to breed, differ consider- 

 ably in plumage from the adult males ; but after the second 

 or third moults they differ only in their beaks having a 

 slight greenish tinge. In the dwarf bitterns (Ardetta), ac- 

 cording to the same authority, "the male acquires his final 

 livery at the first moult, the female not before the third or 

 fourth moult; in the meanwhile she presents an intermediate 

 garb, which is ultimately exchanged for the same livery 

 as that of the male." So again the female Falco peregrinus 

 acquires her blue plumage more slowly than the male. 

 Mr. Swinhoe states that with one of the Drongo shrikes 

 {Dicrurus macrocercus), the male, while almost a nestling, 

 moults his soft brown plumage and becomes of a uniform 

 glossy greenish black; but the female retains for a long 

 time the white striae and spots on the axillary feathers; 

 and does not Completely assume the uniform black color 

 of the male for three years. The same excellent observer 

 remarks that in the spring of the second year the female 

 spoonbill (Platalea) of China resembles the male of the first 

 year, and that apparently it is not until the third spring 

 that she acquires the same adult plumage as that possessed 

 by the male at a much earlier age. The female Bomhycilla 

 carolinensis differs very little from the male, but the ap- 

 pendages, which like beads of red sealing-wax ornament 

 the wing-feathers, *° are not developed in her so early in 



29 The "Ibia," vol. vi., 1864, p. 122. 



30 When the male courts the female, these ornaments are vibrated, and "are 

 shown off to great advantage," on the outstretched wings ; A. Lei th Adams, 

 "Field and Forest Eamblea " 18t3, p 153. 



