l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO7 



specimen from Ban Bua Yai). In short, unless one is to risk naming 

 a population variably intermediate between two other races, no step 

 in this direction should be taken until much more material from the 

 center of the eastern plateau has been carefully examined. 



20. PELLORNEUM RUFICEPS INDISTINCTUM, new subspecies 



Type. — U.S.N.M. No. 336635, adult male, collected at Chiang Saen 

 Kao (lat. 20° 15' N., long. ioo°05' E.), Chiang Rai Province, 

 northernmost Siam, on January 12, 1937, by H. G. Deignan (original 

 number 2188). 



Diagnosis. — Similar to P. r. chthonium, but distinguishable in series 

 by having the rufous of the forehead, crown, and nape a little paler in 

 tone ; the color of the remaining upper parts paler and decidedly more 

 rufescent ; the under parts slightly more strongly washed with a rather 

 warmer buff. 



From P. r. shanense (which occurs in the adjacent Southern Shan 

 State of Kengtung) easily separable by having the general coloration 

 of the upper parts paler in tone ; the light edgings to the feathers of the 

 sides of the neck narrow and inconspicuous ; the dark centers to the 

 feathers of the uppermost back almost invisible or wholly absent; 

 the under parts less extensively washed with buff — the throat almost 

 free of this color. 



Range. — Northern Siam (Chiang Rai Province) ; probably the part 

 of Haut-Laos lying west of the Mekong River. 



Specimens examined. — Siam : Chiang Rai Province : Chiang Saen 

 Kao (2 males), Chiang Rai (i male), Muang Fang (3 males), Ban 

 Muang Sum (i female), Ban Tao Pun (i female), Ban Pang Ai (i 

 male), Doi Khrang (2 males, i female), Wiang Pa Pao (i male, i 

 female) ; Laos: Enclave: Doi Chang Kong (i juvenile male). 



Remarks. — P. r. indistinctuni is but one of several birds that occur 

 in northern Siam only within the Mekong drainage. 



21. PELLORNEUM RUFICEPS OREUM, new subspecies 



Type. — C.N.H.M. No. 78973, adult male, collected at Muong Moun 

 (lat. 2i°42' N., long. I03°2i' E.), Laichau Province, northwestern 

 Tongking, on March 29, 1929, by J. Van Tyne (original number 919). 



Diagnosis. — Distinguished from P. r. indistinctum by having the 

 rufous of the front, crown, and nape and the rufescent brown of the 

 remaining upper parts decidedly deeper in tone; the dark centers to 

 the feathers of the uppermost back more frequently present and 

 rather more sharply defined ; the light edgings to the feathers of 



