SBliTAL SELfSCTTO^. ^6t 



life. The eared pheasant (Orossoptilon miritum), howler, 

 offers a remarkable exception, for both sexes possess the 

 fine caudal plumes, the large ear-tufts and the crimson 

 velvet about the head; I find that all these characters 

 appear very early in life in accordance with rule. The 

 adult male can, however, be distinguished from the adult 

 female by the presence of spurs; and, conformably with 

 our rule, "these do not begin to be developed before the age 

 of six months, as I am assured by Mr. Bartlett, and even 

 at this age the two sexes can hardly be distinguished. * The 

 male and female peacock differ conspicuously from each 

 other in almost every part of their plumage, excejJt in the 

 elegant head-crest, which is common to both sexes; and this 

 is developed very early in life, long before the other orna- 

 ments which are confined to the male. The wild duck 

 offers an analogous case, for the beautiful green speculum 

 on the wings is common to both sexes, though duller and 

 somewhat smaller in the female, and it is developed early 

 in life, while the curled tail-feathers and other ornaments 

 of the male are developed later, f Between such extreme 

 cases of close sexual resemblance and wide dissimilarity, as 

 those of the Orossoptilon and peacock, many intermediate 



* In the common peacock (Pavo crisiatus) tbe male alone possesses 

 spurs, while both sexes of tbe Java Peacock (P. mutieus) offer tbe 

 unusual case of being furnished with spurs. Hen<je I fully expected 

 that in tbe latter species they would have been developed earlier in 

 life than in tbe common peaCock; but M. Hegt of Amsterdam informs 

 me, that with young birds of tbe previous year, of both species, 

 compared on April 23, 1869, there was no difference in tbe develop- 

 ment of the spurs. The spurs, however, were as yet represented 

 merely by slight knobs or elevations. I presume that I should have 

 been informed if any difference in tbe rate of development had been 

 observed subsequently, 



f In some other species of the Duck family the speculum differs in 

 a greater degree in the two sexes; but I have not l)een able to dis- 

 cover whether its full development occurs later in life in the males of 

 such species, than in the males of tbe common duck, as ought to be the 

 case according to our rule. With the allied Mergus cucullatus we 

 have, however, a case of this kind: tbe two sexes differ conspicu- 

 ously in general plumage, and to a ccmsiderable degree in the specu- 

 lum, which is pure white in tbe male and grayish white in the 

 female. Now tbe young males at first entirely resemble the females, 

 and have a grayish- white speculum, which becomes pure white at an 

 earlier age than that at which the adult male acquires his other and 

 more strongly-marked sexual differences: see Audubon, " Ornitholo- 

 gical Biography," vol. iii, 1835, i)p. 249-250. 



