156 



Mr. C. B. Ticehurst on 



[Ibis, 



edging to the inner wel)S, in sonieit reaches further and even 

 half the web may be wliite, and the different stages are found 

 equally in adults and in birds of tiie year. 



Secondly, on measuring I find that, as Gates said, the 

 white-winged birds are on the whole larger. 



•50 (S oreophila, 50 S atrogularis. 



W. (95) 96-104, once 100. W. 92-99 mm. 



T. 67-71. T. 64-71 mm. 



Bill from base 17-0-19 (mostly 17-5-18-o). Bill 16-18-5 (mostly 



16-0-17-6 mm.) 



Though a good many of the two races overlap in bill 

 measurement and about 15 per cent, of oreophila in wing- 

 measurement, yet the differences taken in conjunction with 

 the whiteness of the wing constitute alone sufficient grounds 

 for separation. 



Text-figure 8. 



I 



85 86 87 88 



90 91 32 93 94- 95 96 97 98 99 



As regards females, many show no white in the wing at 

 all and some show a varying amount, up to half the web 

 being white, and most of these latter are large birds. I have 



