8 A MONOGRAPH OF THE PHEASANTS 
the apparent quick reaction of the plumage pigment to the environmental conditions. 
At the time I wrote of this in my descriptions again and again, and I have allowed 
these interpretations to stand in the monograph text. But I cannot accept this 
explanation as covering the entire question. The same thing has struck Baker, and he 
tends to give humidity and other meteorological factors considerable weight. Speaking 
of the Himalayan birds, of the Lineated and the Silver Kaleege respectively, he says, 
“Thus we find that the black and very dark birds inhabit areas of dense forest at com- 
paratively low elevations where there is a heavy rainfall, and which are therefore well 
provided with rivers, lakes and swamps. Next we see that the grey birds inhabit 
hills of moderate height covered with mixed forest, bamboos and grasslands, and with 
a moderate rainfall. Thirdly, we obtain the white birds only in hills and plateaux at 
a considerable elevation where the grass-covered and open country exceeds in extent 
the forest, and where the rainfall is slight or even scanty. 
“We thus have it demonstrated that great humidity and heat, with its constant 
tropical growth of vegetation, induces black in the plumage of the birds of this genus, 
whereas the coldness of the higher mountains, combined with a drier atmosphere and 
its consequent higher forests and more open grasslands, induces white. These four 
factors, temperature, humidity, elevation, and vegetable growth, we shall find, therefore, 
are the principal ones governing not only the differentiation of the species, but also 
of the intermediate subspecies.” 
Believing thoroughly, as I do, in the darkening effect of humidity, it seems 
reasonable that this explanation is correct. But I am convinced that it only partly 
explains the changes in coloration, and that we shall have to await the discovery of 
unknown factors to be certain. I have kept Himalayan and Silver Kaleege in captivity, 
under the same extremes of humidity, for many years, have cross-bred and bred them 
pure, and I have never noticed any change in successive moults or successive generations, 
either toward melanism or albinism. As I shall mention elsewhere I have shot wild 
birds from the same flock which differed widely from one another, and in Fokien I 
have found Silver Kaleege living in numbers in low, coastal, humid country. While 
these arguments are only partial, yet they make us wary of accepting a wholesale 
explanation of the Kaleege pigmentation. It is a problem of transcendant interest, 
which it is hoped may be elaborated before these birds become extinct in their native 
haunts. 
KEY TO GENNAEUS 
I. Colour dominately black and white (males). 
a Lesser and median wing coverts black and white. 
a Black and white equal ; : : : : : : : : : . lineatus. 
&' White dominant over black. 
a’ (Outer web of outer tail feathers streaked with white : ; : : . nycthemerus. 
6 Outer web of outer tail feathers wholly black 5 : : : : . whitehead. 
b Lesser and median wing coverts glossed with blue. 
c’ Crest white . ; : . : : , j : ; : : : . albocristatus. 
ad Crest black. 
te 
c’ Under parts greyish white. 
a” Rump fringed with white . 5 i : . . : : 4 . Leucomelanos. 
0” Rump not fringed with white. . . 3 : : : ; .  melanonotus. 
a’ Under parts black , ; ‘ : ; ; : Ane : . _ horsfieldi. 
