134 Lord Walden on a further Collection of 
say and Wimberley, in no material respect differ from Sikim 
and Ceylon individuals; nor am I enabled to find any impor¬ 
tant character whereby they can be separated from Seychelles, 
Mauritius, or Reunion examples [Hirundo francica, Gm.). 
The dorsal feathers in all examples from the above-named 
localities have the tips of the basal portion of the webs pure 
white. This can only be detected by parting the feathers; for 
the overlapping terminal and exposed part of the dorsal fea¬ 
thers is uniform smoke-brown. The extent of white on the 
edging of the webs increases as the feathers descend the back, 
so that those which clothe the uropygium have more of the 
edges of their webs, both in length and breadth, coloured 
white. The result is that the white sometimes becomes par¬ 
tially exposed. In some of the shorter of the upper tail- 
coverts the white colour of the webs is still more developed, 
occasionally forming a conspicuous white edging ; but no 
•covert is entirely white, the tip and central part of each being 
of a varying shade of mouse-colour. It is thus that the al¬ 
bescent or pale mouse-coloured band on the rump observable 
in many examples of this species is produced; and it is fre¬ 
quently made more prominent in the dried skins by the mode 
of preparation of the specimens. In three examples of true 
C. francica from Mauritius and Reunion, kindly lent to me 
by Professor Newton, a pale band is discernible; in another 
from the Seychelles it is absent. In a Ceylon individual in 
the collection of Mr. Holdsworth it is also entirely wanting. 
My Sikim specimens have the band as much developed as in 
those from Mauritius; and Andaman birds are not to be dis¬ 
tinguished, all of them exhibiting, more or less, a pale band 
on the rump. That there is a tendency in this section of the 
genus Callocalia to evolve a pure white band on the rump is 
shown in C. troglodytes and other more eastern species, in 
which we find it a permanent and well-determined character. 
But in none of the races of the species under notice does it 
appear to be stable, or sufficiently and constantly developed 
to make it a trustworthy differential character. In all other 
essential respects birds from the localities alluded to are iden¬ 
tical ; and I therefore adopt GmelhPs title as being the oldest. 
