AKT. 4 BIRDS OF THE MENTAWI GROUP RILEY 29 



material shows, there is only one well-defined form of this type on the 

 islands off the west coast of Sumatra. 

 The various series measures as follows: 



Four males, Nias: Wing, 87-96 (91); culmen, 15.5-17 (16.4). 



Three males, Simalur: Wing, 90-93 (90); culmen, 16-17 (15.5). 



One male, Pulo Babi : Wing, 96 ; culmen, 16.5. 



One male, Sipora : Wing, 93 ; culmen, 18. 



Two females, Nias: Wing, 84; culmen, 16. 



Two females, Simalur: Wing, 86; culmen, 15-16 (15.5). 



One female, Pulo Babi : Wing, 84 ; culmen, 16.5. 



One female,'* Pulo Lasia (type) : Wing, 92; culmen, 17. 



Type of K. m. paffiensis,^ wing, 84 ; culmen, 16. 



ORTHOTOMUS SEPIUM CONCINNUS RUey 



Orthotomus seplum concinnus Rilett, Proc. Biol. Soc. Washington, vol. 40, 



1927, p. 96 (Sipora Island). 

 Orthotomus sepium ochromtnatns? Chasen and Kloss, Ibis, 1926, p. 292. 



Eight males and six females, Sipora; three males, three females, 

 and five unsexed birds, Siberut. 



Judging by the few adult males from Siberut, the Sipora and Siberut 

 birds belong to the same form. Both series agree in being lighter, 

 purer gray above, with the head and throat lighter cinnamon than 

 Orthotomius senium ochromtnatus Oberholser, of the Pagi Islands. 

 Orthotomus sepium haeus Oberholser, of Nias Island, is darker and 

 nearer cineraceus than the Pagi Island form and need not be 

 considered here. 



The series from the various Mentawi Islands measure as follows: 



Eight males, Sipora: Wing, 43.&-50 (47.2) ; culmen, 14.5-15.5 (14.9). 



Three males, Siberut: Wing, 46-51 (48.7) ; culmen, 15-15.5 (15.2). 



Four males, Pagi Islands (North Pagi, 3; South Pagi, 1): Wing, 50--52 



(50) ; culmen, 14.5-15.5 (15). 

 Six females, Sipora: Wing, 44-47.5 (45.9) ; culmen, 14-15 (14.4). 

 Three females, Siberut: Wing, 43-46.5 (45) ; culmen, 14.5-15 (14.8). 

 One female. North Pagi Island : Wing, 48.5 ; culmen, 14. 



LANIUS TIGRINUS Drapiez 



Lanius tigrinus Dbapiez, Diet. Class. Hist. Nat., vol. 13, 1828, p. 523 (Java). 

 Lanius tigrinus Chasen and Kloss, Ibis, 1926, p. 292. 



A series of nine immature birds from Siberut and three from 

 Sipora. 



The series from Siberut were taken September 18-October 2 ; those 

 from Sipora October 29-November 3. 



The United States National Museum possesses two immature ex- 

 amples from Simalur Island, November 25 and December 12, and 

 three from Tana Bala, Batu Islands, February 6-13. 



" Marked as a female, but probably a male. 

 "^ Marked male, but probably a female. 



