THE BIRDS OF NORTHERN THAILAND 339 



As Ticehurst has correctly observed (Journ. Bombay Nat. Hist. 

 Soc, vol. 36, 1933, p. 924) : "On comparing burmanicus and flaveolus 

 with the Javanese bird {gularis of Horsfield) one would hardly hesi- 

 tate to say that here we have geographical representatives of one 

 species." In the arrangement above, C. ochraceus differs from tephro- 

 genys precisely as C. flaveolus from xanthizurus and if the latter pair 

 be united under the name flaveolus, consistency demands a similar 

 combination of ochraceus and tephrogenys to form a second species or 

 superspecies tephrogenys. 



The alleged overlaps in the ranges of C. ochraceus and C. tephro- 

 genys seem to be merely superficial — the races of tephrogenys keeping 

 to lower elevations everywhere, those of ochraceus to higher elevations 

 in the general areas inhabited by tephrogenys and appearing in the 

 lowlands only where tephrogenys is absent. We have then a problem 

 not unlike that set in the Indo-Chinese countries by the juxtaposition 

 of boreal and tropical representatives of Sitta europaea (which see) 

 but more complicated by the fact that within the assemblage of ochra- 

 ceus forms a second trenchant differentiation has taken place, to form 

 what for convenience I have called the northern and southern groups. 



A distributional study restricted to these two groups will reveal 

 on a smaller scale the same puzzles that appear in a similar study of the 

 two main branches of the superspecies : thus, in South Annam, a bird 

 near to C. o. ochraceus occurs but a few miles from localities at which 

 C. o. annamensis is found, without the least sign of intergradation be- 

 tween the two. This may be explained by the assumption that annam- 

 ensis (the extreme representative of the northern group) pressing 

 southward has here met the northward-pressing ochraceus (of the 

 southern group) , with the result that, in the same general area, we have 

 conspecific forms so remotely related in time as to act like distinct 

 species. 



MICROSCELIS CHARLOTTAE PROPINQUUS (Oustalet) 

 TONGKINESE VlRIDESCENT BULBUL 



Criniger propinquus Oustalet, Nouv. Arch. Mus. [Paris], ser. 4, vol. 5, 1903, pp. 

 76-77 (Pa-mou, Tongking). 



Criniger lonnbergi Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., vol. 50, No. 8, 

 1913, p. 24 ("Northern Siarn ... at Bang Hue Horn [= Ban Huai Horn] 

 and Kao Plyng [= Khao Phlung]" ; type specimen from Ban Huai Horn, fide 

 Gyldenstolpe, Ark. for Zool., vol. 19A, No. 1, 1926, p. 57). 



Iole olivacea, Gyldenstolpe, Journ. Nat. Hist. Soc. Siam, 1915, p. 166 (listed). 



Criniger lonnbergi, Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., 1916, p. 68 

 (Khun Tan, Pha Hing, Doi Pha Sakaeng, Pang Hua Phong, Pha Kho). 



Iole olivacea lonnbergi, Gyldenstolpe, Ibis, 1920, p. 491 ("Northern and north- 

 western Siam"). — de Schauensee, Proc. Acad. Nat. Sci. Philadelphia, 

 1929, p. 538 (Doi Suthep, Chiang Saen). — Chasen and Boden Kloss, Journ. 

 Siam Soc. Nat. Hist. Suppl., 1932, p. 242 (Doi Suthep). 



