658 Messrs. Sclater and Mackworth-Praed on [Ibis, 



admits a large percentage of wanderers from other districts. 

 The explanation probably lies in the colour or nature of the 

 soil. In Senegal and again in northern Nigeria round Lake 

 Chad the palest form occurs. This is a bird of which the 

 general tone is pale grey aud yellow. Nest, from Gambia 

 round the coast to Southern Nigeria and along the Shari 

 comes a form with a distinctly rufous or vinous tinge, which 

 is particulai'ly noticeable on the shoulders and wing-coverts. 

 Thirdly, from the upper Welle and western Lado Enclave 

 comes a form of which the prevailing tinge is rich rufous, 

 almost chocolate. A fourth form from the White Nile below 

 Kaka and from the Blue Nile is most like the Senegal form, 

 but the yellow is richer and the scapulars more boldly 

 marked. The last form and the most distinct of all is very 

 dark grej-^, almost black, and comes from the country east of 

 Lake No to the Sobat river and about as far north as Kaka 

 on the White Nile. 



Of the examples in the present collections most of the 

 birds belong to the fourth form alluded to above, but the 

 two from Tonga in the Chapman & Lynes collection are 

 very richly coloured specimens of the fifth and last-mentioned 

 group, while the Meridi bird approaches the rufous form 

 from the upper Welle and Lado. 



Macrodipteryx longipennis. 



Caprimuli/us lonyipennis Shaw, Nat. Misc. viii. 1796, 

 pi. 265 : Sierra Leone. 



Macrudvpteryx viacrodipterus (Afz.) ; Reichw. V. A. ii. 

 p. 370. 



Macrodipteryx longipennis (Shaw) ; Butler, Ibis, 1905, 

 p. 345, 1908, p. 239, 1909, p. 84; C. Grant, Ibis, 1915, 

 p. 302. 



[B. coll.] 1 Gediiref May, Kas. ; 1 Gardain ApL, 1 Tonj 

 Jan. B.G. ; 1 Mongalla, summer. 



[Chr. coll.] 1 Meridi Jan. B.G. 



Mr. Butler has written at some length on this species, 

 which is a resident and known to breed in the Sudan. 



