BIRDS FROM SIAM AND THE MALAY PENINSULA 61 



extends the range considerably to the northward. This makes only- 

 three records for Siam, but it is probably commoner than the records 

 indicate, especially in the southern part of the Peninsula. 



A related form, Rhizothera longirostris dulitensis Ogilvie-Grant, 

 occurs in northern Borneo. 



MELANOPERDIX NIGRA NIGRA (Vigors) 



Crrjptonyx niger Vigors, Zool. Journ., vol. 4, p. 349, 1829 (Sumatra). 



Dr. W. L. Abbott collected an adult male at the Endau River, east 

 coast of Johore, June 25, 1901, and another adult male at the Rum- 

 pin River, Pahang, June 24, 1902. "Bill black; iris deep brownish 

 red." 



These two males are the only specimens from the Malay PenLusula 

 in the United States National Museum, but it has a fair series from 

 Borneo and Sumatra. Birds from Borneo have been named Melano- 

 perdix nigra borneensis, by Rothschild,^^ but Robinson and Kloss ^* 

 have questioned their distinctness. After examining a series of nine 

 males from Sumatra, the two males from the Malay Peninsula, and 

 five males from Borneo, I fail to see any constant differences in this 

 sex. The lighter and somewhat more slaty edges to the feathers of 

 the upper side, spoken of by Lord Rothschild as one of the distin- 

 guishing characters of borneensis, are, in my opinion, due to age, as 

 two of the males in the Bornean series are slightly immature and lack 

 this feature, while some males in the Sumatran series have it and in 

 some these lighter edges are much reduced. 



Five females from Sumatra compared with four females from Borneo 

 appear to be darker above and below, especially on the belly, and the 

 form is worthy of recognition on the differences in this sex. 



There appears to be little or no difference in size between the two 

 series. 



Nine males from Sumatra measure: Wing, 131-143 (137) ; tail, 60-70 

 (64); culmen, 18.5-21 (19.9); depth of upper mandible at base, 9.5-10.5 

 (10) mm. 



Five males from Borneo: Wing, 132.5-143 (137.3) ; tail, 59-64 (62.6) ; 

 culmen, 18.5-21 (19.7); depth of upper mandible at base, 10-10.5 

 (10.2) mm. 



The two males from the Malay Peninsula: Wing, 137-140; tail, 

 60-60; culmen, 21-21.5; depth of upper mandible at base, 10-11 mm. 



Five females from Sumatra: Wing, 135-143 (139.5); tail, 59.5-67 

 (62.6); culmen, 18-20 (18.9); depth of upper mandible at base, 10-10.5 

 (10.2) mm. 



Four females from Borneo: Wing, 131-144 (137.4); tail, 58-65 (62); 

 culmen, 18.5-20 (19); depth of bill at base, 10-10.5 (10) mm. 



•sBull. Brit. Orn. Club, vol. 38, p. 3, 1917. 

 Mlbis, 1918, p. 592. 



33527—38 6 



