1 34 Lord Walden on a further Collection of 



say and Wimberley, in uo 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 ramp 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 Gmelin's title as being the oldest. 



