BIRDS FROM SIAM AND THE MALAY PENINSULA 29 



brownish or blackish in the adult. Only rarely do adults of A. hacchus 

 have the outer primaries entirely white like speciosa, and these are 

 probably very old birds. My series of A. grayii is not sufficient to 

 say whether the adults ever have the tips of the outer primaries 

 white. The immatures of both A. hacchus and A, grayii have the 

 outer primaries more or less dusky on the outer webs and tip, varj^'ing 

 in degree probably with the age of the specimen. The immatures 

 that I have assigned to A. speciosa continentalis have the primaries 

 entirely white or with almost an imperceptible trace of grayish on 

 the outer web of the first primary. 



The adults of the three species may be separated by the following 

 key: 



1. Back claret brown, wnth a slight slaty wash; neck dark olive-buff grayii 



Back slate color; neck not olive-buflf 2 



2. Pileum and upper neck clay color speciosa 



Pileum and upper neck prussian red bacchus 



Both speciosa and grayii have the nuchal plumes white at the tips; 

 these are lost after the breeding season. 



Ardeola speciosa speciosa (Horsfield), of Java, Sumatra, Celebes, 

 Borneo, and Sumbawa, is very similar to continentalis but apparently 

 somewhat smaller. With only one adult of the latter before me, it 

 is impossible to pass judgment on its distinctness, however. 



The measurement of the wing in four males from Celebes is as 

 follows: 205, 207, 209, 210 mm; in two males from Java, 192, 200 mm. 



The wing in the single male of continentalis measures 213 mm; the 

 wings in the three males (that I have called immature, but may really 

 be the winter plumage) measure 220, 225, 234 mm. The bill in 

 continental specimens also seems to average somewhat larger. The 

 culmens in the four males from Siam measure 62-66.5 (64.9) mm; 

 two males from Java and four from Celebes measure 59-64 (60.9) mm. 

 The adults from Celebes were taken in winter and are without the 

 nuchal plumes, and they are not in the streaked winter plumage; 

 here they probably breed early and the breeding plumage is acquired 

 early, the nuchal plumes being the last to be assumed. 



Just what the range of Ardeola speciosa continentalis embraces is 

 not known at present. So far it has been recorded only from Siam, 

 Tenasserim, and the south of Indo-China.^° It is quite possible the 

 Sumatran records also belong to it. 



BUBULCUS IBIS COROMANDUS (Boddaert) 



Cancroma corornanda Boddaert, Table des planches cnlumin^ez d'histoire 

 naturelle, p. 54, 1783 (Coromandel Coast). 



One adult male in breeding plumage and three adult males in 

 winter plumage, Bangkok, May 27, 1926, August 9, 1924, and 

 December 29, 1925. 



w See Dclacour and Jabouille. Oiseaus I'Indochlne Francaiso, vo). 1, p. 64, 1931. 

 33527—38 3 



