200 Mr. E, C. Stuart Baker on [Ibis, 



if constant, would entitle it to subspecific rank, and that 

 is tlie immaculate upper back and scapulars. Of the five 

 Siamese specimens I have examined, four have these parts 

 quite immaculate, and the fifth almost so. Mr. Kloss does not 

 mention this feature, so presumably his specimen — a single 

 one again — was barred on the upper back. Of course, 

 specimens with the back and scapulars immaculate are found 

 everywhere, and there are such specimens in the British 

 Museum collection from Kumaon, Nepal, Behar, and 

 Tenasserim. Such are, however, quite exceptional, and it is 

 curious that the only five examples of the Siam bird which I 

 have been able to examine should be all alike in this respect. 

 As regards colour-variation, nothing further need be said 

 except that I cannot find the slightest difference between 

 the races named mesos, bhjthii, hurmanicus, and humei, so 

 that eventually we are thrown back upon variation in size 

 alone if we wish to divide p/iaioceps, brachyurus, or gidaris 

 into further local races. 



Micropterniis brachyurus brachyurus group. 

 The following table gives the measurements of adult 

 non-moulting birds in the Museum collection. The places 

 cited are those marked on the labels, but some birds with 

 nou authentic data have been omitted : — 



Sumatra Wing 101-114 mm. Average 106'5. 8 specimens. 



South Malay, 

 various places . . ,, 106-115 mm. „ 110-2. 15 „ 



Malacca „ 99-115 mm. ,, 107-5. 26 



Singapore .... „ 113-117 mm. „ 114-5. 3 „ 



*Tenasserim „ 107-132 mm. ,, 121-5. 56 „ 



Klang , 109-116 mm. „ 110-0. 12 



Measurements would thus seem to show that we have two 

 races of brachyurus, one from Sumatra and the southern 

 Malay Peninsula, with a wing averaging under 110 mm., 

 and never exceeding 117 mm,, and a second race from the 

 northern Malay, Siamese and Burmese peninsular areas, 

 with a wing averaging over 121 and seldom under 115 mm. 



* This includes birds as far north as the north of peninsular Siam and 

 Burma, but the largest bird, a female, with wing of 132 mm., comes 

 from Amherst. 



