158 A MONOGRAPH OF THE PHEASANTS 
I have said that the disappearance of the crimson is apparently abrupt, because 
this is true only from a superficial point of view. The crimson persists on almost 
all the body plumage, much darkened, however, and purpled by the encroaching black. 
A feather from the mid-back shows a shining blue terminal band of 5 mm. in 
width. This exhibits the peculiar wrinkle or upward bending of the vane which 
I described in Lofhura. Bordering on this blue band is a well-marked zone of dark 
_purplish-crimson, which merges into the proximal dull black. 
The change in colour of the crimson zone is most interestingly correlated with 
a corresponding alteration in structure. The barbules are almost as short as in the 
pure crimson nuchal region, but with the blackening of the bright colour barbicels 
appear, and throughout the entire area-from four to six of these tiny hooklets are present 
on every barbule. Thus the barbs of this zone tend to cohere to one another, while 
the shortness of the barbules results in a much closer approximation of these barbs than 
usual. This results in a springing apart of the web in a number of places, and produces 
the curious split-up appearance of the feathers of the White-tailed Pheasant, a character 
I have observed in no other bird. The terminal part of each feather is usually split 
apart into eight or ten divisions, each consisting of a greater or less number of barbs 
very closely cohering to one another. 
The feathers of the rump are short and truncate, very sharply set off from the 
upper tail-coverts. These latter are long, somewhat curved and pure white, so that 
in both form and colour they resemble the tail-feathers themselves. 
As the tail of this unusually interesting pheasant is its chief glory and the most 
specialized in colour and number of feathers of any tail in the family of pheasants, it 
is well worth considering in some detail. In the fully adult male the entire tail is pure 
white, and at this age the usual, normal number of feathers—certainly the maximum 
number—is thirty-two, just 7wece as many as in the somewhat allied genus Lophura. 
It is not often that the complete number is present, one or more usually having been 
pulled out in some way. After very careful examination of the roots of the tail-feathers 
and the surrounding skin by the complete relaxation of many adult male birds, I am 
_convinced that it is not uncommon for thirty to be the total number. It is a very easy 
matter to detect the location of missing feathers, and in a number of cases where thirty 
feathers were present, or that number as represented by the total number of follicles, 
I have satisfied myself that there was absolutely not a single feather missing, nor any 
additional unoccupied follicles. In such a specialized organ as the tail of this pheasant 
such variation is surprising, and is of especial interest in view of the variation in 
number of rectrices in the species of Cvossoptilon. Thirty-two, however, may be 
taken as the maximum, usual number of tail-feathers in the adult male White-tailed 
Pheasant. 
As we shall see, the number of rectrices in the chestnut tail of the second-year 
male is twenty-four, so that-in the succeeding or third annual moult there is an increase 
of eight feathers. When the tail of a freshly killed pheasant is spread widely the 
feathers seem to be in quite regular alignment, but as the tail is allowed slowly to 
close, an irregularity becomes apparent, and we find that this occurs solely among the 
central eight or ten pairs. Comparison of fully adult birds with those in the chestnut- 
tail plumage, and of individuals moulting from one to the other show clearly that the 
