THE BIRDS OF NORTHERN THAILAND 219 



of the neck, beneath the feathers, purple-blue ; the naked skin under 

 the wings bluish slate ; the bare skin inside the tibiae and on the sides 

 of the abdomen livid plumbeous; the naked skin around the vent 

 plumbeous-blue; the feet and toes slaty gray, tinged olive; the soles 

 dull brownish ; the claws dark brown, with the apical half black and 

 the underside horny white. The adult male differs chiefly in having 

 the gular skin bright orange-yellow. 



In the present form the casque is reduced to a low, corrugated out- 

 growth on the basal half of the culmen, and there are still lower ridges 

 on the sides of both maxilla and mandible at the base. The male has 

 the forehead shining, deep purple-chestnut, this color continuing as 

 a narrow line down the center of the crown and broadening posteriorly 

 to include the whole of the bushy crest ; the feathers of the rest of the 

 head and the whole foreneck shining buffy white; the tail white; the 

 rest of the plumage black, glossed with steel green. The female dif- 

 fers in having the entire plumage black, except for the white tail. 



I have found no example of Rhyticeros subruficollis from our area 

 in either Hannover or Stockholm and feel certain that Gyldenstolpe's 

 records for that bird are based upon sight misidentifications of tice- 

 hursti, although, in his "List of the Birds of Siam" (1920), he states 

 that he "obtained it at the Meh Lem River in northern Siam." 



ACEROS NIPALENSIS (Hodgson) 

 RUFOUS-NECKED HORNBILL 



Buceros Nipalensis Hodgson, Asiatic Researches, vol. 18, pt. 1, 1833, pp. 178-186, 



fig. 1,2 (Nepal). 

 Aceros nepalensis, de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 1929, p. 573 



(Doi Suthep) ; 1934, p. 263 (Doi Suthep). 

 Aceros nipalensis, Deignan, Journ. Siam Soc. Nat. Hist. Suppl., 1931, p. 162 (Doi 



Suthep) ; 1936, p. 95 (Doi Suthep).— Riley, U. S. Nat. Mus. Bull. 172, 1938, 



p. 195 (Doi Langka). 



The rufous-necked hornbill is known in our provinces only from 

 some of the higher peaks of the districts west of the Khun Tan range, 

 where it is a not rare but seldom observed resident of the heaviest ever- 

 green. I found it common on Doi Ang Ka at 6,000 feet and fairly so on 

 Doi Suthep from 3,300 to 5,500 feet. Smith took one from a party of 

 seven or eight on Doi Langka. 



I have always seen this species in pairs or small flocks, usually in the 

 tops of lofty trees, but once feeding upon fruit fallen to the ground. 

 Its ordinary note is a loud croak, and in flight the wings produce a 

 sound like that made by our other large hornbills. 



I took a male with enlarged gonads on Doi Suthep at 3,300 feet, 

 January 22. Smith's female from Doi Langka, April 29, is molting 

 the central rectrices. 



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