)iup, XV. Birds — Colour and Nidificatiou. 457 



bave not had their bright colours eliminated through natural 

 selection, the males often differ in a slight, and occasionally in a 

 considerable degree, from the females. This is a significant fact, 

 for such differences in colour must be accounted for by some of 

 the variations in the males having been from the first limited in 

 transmission to the same sex ; as it can hardly be maintained that 

 these differences, especially when very slight, serve as a protec- 

 tion to the female. Thus all the species in the splendid grouj} 

 of the Trogons build in holes ; and Mr. Gould gives figures 21 of 

 both sexes of twenty -five species, in all of which, with one partial 

 exception, the sexes differ sometimes slightly, sometimes con- 

 spciuously, in colour, — the males being always finer than the 

 females, though the latter are likewise beautiful. All the species 

 of kingfishers build in holes, and with most of the species the 

 sexes are equally brilliant, and thus far Mr. Wallace's rule holds 

 good ; but in some of the Australian species the colours of the 

 females are rather less vivid than those of the male ; and in oue 

 splendidly-coloured species, the sexes differ so much that they 

 were at first thought to be specifically distinct.' 22 Mr. B. B. Sharpe, 

 who has especially studied this group, has shewn me some 

 American species (Ceryle) in which the breast of the male is 

 belted with black. Again, in Carcineutes, the difference between 

 the sexes is conspicuous : in the male the upper surface is dull- 

 blue banded with black, the lower surface being partly fawn- 

 coloured, and there is much red about the head ; in the female 

 the upper surface is reddish-brown banded with black, and the 

 lower surface white with black markings. It is an interesting- 

 fact, as shewing how the same peculiar style of sexual colouring 

 often characterises allied forms, that in three species of Dacelo 

 the male differs from the female only in the tail being dull-blue 

 banded with black, whilst that of the female is brown with 

 blackish bars ; so that here the tail differs in colour in the two 

 sexes in exactly the same manner as the whole upper surface in 

 the two sexes of Carcineutes. 



With parrots, which likewise build in holes, we find analogous 

 cases : in most of the species both sexes are brilliantly coloured 

 and indistinguishable, but in not a few species the males are 

 coloured rather more vividly than the females, or even very 

 differently from them. Thus, besides other strongly-marked 

 differences, the whole under surface of the male King Lory 

 (Aprosmictus scapulitus) is scarlet, whilst the throat and chest of 

 the female is green tinged with reel: in the Euphema spleiidida 



21 See his ' Monograph of the ' Handbook to the Birds of Aus- 

 rrogonidae,' first edition, tralia,' vol. i. p. 133 ; see, also, \ p 



82 Namely Cyanalcyon. Gould's 130, 136. 



