THE BIRDS OF NORTHERN THAILAND 367 



Doi Suthep occurring commonly from that altitude to the summit 

 and on Doi Ang Ka uncommonly from 5,500 to 6,500 feet. 



It is a less numerous and rather more silent bird than the black- 

 capped sibia, and it is accordingly less often observed. The habits 

 of the two seem to differ in no important particulars. 



All of a series of seven adults collected between July 13 and Novem- 

 ber 12 are in postnuptial molt. 



An adult male had the irides brown; the eyelids plumbeous; the 

 bill black, with the basal half of the mandible yellow ; the feet and 

 toes bright yellow ; the claws brownish horn. 



The adult has the upper half of the head and the anterior half 

 of the back black, the feathers of the center of the nape and upper 

 back with broad ashy- white edges to give a streaked appearance ; the 

 scapulars and the lower back, rump, and upper tail coverts chest- 

 nut, sometimes more or less maculated with black on the scapulars and 

 the center of the back; the wings black, the greater coverts tipped 

 with chestnut, the remiges narrowly edged along the outer web with 

 ashy-white, the inner secondaries with narrow white tips as well; 

 the rectrices black, with outwardly increasingly broad white tips (con- 

 spicuous from beneath) ; the underparts white, changing to rich buff 

 on the flanks, lower abdomen, and under tail coverts. 



This is a poorly defined race, variably intermediate between davisoni 

 (of which eximia is doubtless a synonym) and annectens and recog- 

 nizable only in series. De Schauensee has a unique example from Doi 

 Suthep (Acad. Nat. Sci. Philadelphia No. 112261) which might well 

 be called true davisoni, and it is quite possible that davisoni will 

 prove to be the form of Doi Ang Ka, whence no skins are yet known ; 

 on the other hand, a worn specimen from Doi Hua Mot could easily 

 be considered annectens. A series of six from Doi Pha Horn Pok, 

 in good plumage, are consistently paler than saturata and they alone 

 may perhaps properly be placed with the following race. 



LEIOPTILA ANNECTENS ANNECTENS Blyth 



Indian Chestnut-backed Sibia 



L[eioptUa] annectans [sic] Blyth, Journ. Asiat. Soc. Bengal, vol. 16, 1847, p. 

 450 (Darjiling). 



De Schauensee's collectors, between January 22 and February 18, 

 1938, took five males and one female on Doi Pha Horn Pok, 6,000 to 6,400 

 feet. This subspecies is not likely to occur at any other Thai locality. 



In series, annectens differs from saturata in having the chestnut of 

 the scapulars, lower back, rump, and upper tail coverts somewhat 

 paler. 



