A REVISION OF THE GENUS GENN^US. 681 



parts rich blackish brown, the feathers marked with bold concentric 

 bars of rich fulvous, not with longitudinal strise as in lineahis. 

 Legs red. 



Distributio7i. — The area inhabited by this sub-species may be said 

 Ito be the inter Irrawaddy-Salwin District from about 26-50'^ latitude 

 N. to about 21-50° or rather further South. 



It will be seen that the area occupied by this sub-species is very 

 much greater than that inhabited by any other, but, at the same 

 time, it is a well-defined area between two big rivers, the Irrawaddy 

 and the Salwin, on the West and East ; whilst on the South it is to 

 a great extent divided from sliarpei by the dry area from Mandalay 

 and Maymyo on the North to Meiktila and Taungyi on the South, 

 in which Silver Pheasants appear to be very rare. 



The extent to which rufipes must be held to absorb other species 

 named by Oates and others is a question which has given me infinitely 

 more need for thought than the consideration of the whole of the 

 other forms put together. In the area which I now claim holds but 

 one good and one doubtful sub-species, Oates and others have 

 named the following thirteen species : — G. rufifes, jonesi, ripponi, 

 atlayi, assiwdlis, elegans, granti, affinis, liaringtoni, andersoni, nishetti, 

 crawfurdi and nyctkemerus. 



At first sight, this would seem to show that I must be wrong in 

 admitting but two sub-species, but a careful analysis of the position 

 will possibly prove my contention to be right. In the first place a 

 glance of the Map No. 2 will show that throughout the wide area 

 over which this bird, rufipes, is distributed, there is no very large 

 river to check distribution, and with the other sub-species we find 

 that, almost invariably, rivers form the boundaries which divide one 

 from another. It is true that along the valleys of some of these 

 boundary rivers another species, horsfieldi, is to be found at the 

 lowest altitudes, but still we have a definite boundary to the hills 

 which prevents access, except in exceptional cases, from one area to 

 another. But in the area occupied by rufipes, there is no crossing 

 of such boundary, and therefore there is only one other cause which 

 would check the spread of a species, or sub-species, viz., a sudden 

 alteration in the elevation of the country and a corresponding 

 change in climate and vegetation. There is, however, no change ot 

 this character in elevation, and the bird spreads accordingly. At 

 the same time, the South centre of the area marked on the map as 

 being the habitat of this bird is much drier and lower, and here, 

 accordingly, the bird has not yet been obtained. 



An examination of all the material obtainable proves that even 

 in the area occupied by rufipes, the same laws that have in other 

 parts of Burmah evolved species and sub-species are in force here also, 

 in consequence of which we find that, on an average, the whitest 

 birds are to be found on the highest, most open plateaux and 

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