28 BULLETIN 17 2, UNITED STATES NATIONAL MUSEUM 



In a series of 18 breeding adults of bacchus from China there are 

 only two that have the outer primaries entirely white at the tip; in 

 speciosa, all the breeding specimens examined, except one, have 

 entirely white primaries. This seems to hold for winter birds. My 

 series of grayii is too Uinited to enable me to work out the differences 

 between winter and immature specimens of it and specimens of bacchus 

 taken at the same time; bacchus, however, seems to have a thicker, 

 heavier bill. 



Nine breeding males from China (where grayii does not occur) 

 measure: Wmg, 215-240 (227.8); culmen, 61-65 (63); depth of bill 

 at posterior border of the nostril, 14-15.5 (14.9); tarsus, 55.5-64 

 (59.2) ; middle toe and nail, 57-64 (59.7) mm. The female is somewhat 

 smaller. Seven breeding females from China measure: Wing, 

 197-222 (209.4); culmen, 60-63 (60.4); depth of bill at posterior 

 border of nostril, 13-15 (13.8); tarsus, 56-63 (57); middle toe and 

 claw, 54-62 (57) mm. 



The range of the species extends from northern China south 

 through eastern Assam, Burma, Siam, and Indo-China to the Malay 

 Peninsula and Borneo. Migratory m the northern part of its range. 



I consider whiter records of this species very uncertain and do 

 not quote them. Robinson and Kloss ^* say it is rarer than grayii in 

 Peninsular Siam but hard to distinguish except in the breeding 

 season; Deignan ^^ reports that at Chiengmai it is much less common 

 during the breeding season than A. grayii. 



It may be that in the extreme south of its range it is only a winter 

 straggler and does not breed. 



ARDEOLA SPECIOSA CONTINENTAUS Salomonsen 



Ardeola speciosa continentalis Salomonsen, Orn. Monatsb., vol. 41, p. 41, 1933 

 (Bangkok, Siam). 



One adult breeding male and two immature males, Bangkok, 

 February 15 and April 23, 1924, December 26, 1925; one immature 

 male. Bung Borapet, March 21, 1933. 



Dr. W. L. Abbott took a female at Tanjong Badak, Tenasserim, 

 December 29, 1900. This bird has the primaries including the tips 

 and shafts wliite; wing, 195 mm. I feel quite certain that it belongs 

 to this form. 



Three breeding species of Ardeola occur in Siam, and while the 

 adults in breeding plumage are easily differentiated, the young and 

 immature are very difficult to separate. A. speciosa in any plumage 

 usually has the primaries entirely white. Immature specimens 

 have the outer primaries brownish at the tip, but not to the same 

 extent as grayii or bacchus. A. bacchus and A. grayii have the two 

 or tliree outer primaries gray on the outer web and tip and shafts 



M Journ. Nat. Hist. Soc. Siam, vol. 5, p. SO, 1921. 



«» Journ. Siam Soc. Nat. Hist. Suppl., vol. 8. p. 173, 1931. 



