522 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



THALASSEUS BERGII HALODRAMUS, new subspecies. 



Subspecific characters. — Similar to Thalasseus hergii cristatus, but 

 upper parts much paler. 



Description.— Type, adult male, No. 191382, U.S.N.M.; Pata 

 Island, near Sulu Island, southern Phihppine Islands, November 25, 

 1903; Dr. E. A. Mearns. Forehead white; crown duU white, heavily 

 spotted with fuscous black; an occipital crest of pointed feathers 

 black, many of them sUghtly tipped with whitish; broad cervical 

 collar white ; rest of upper surface gray, between Ught mouse gray and 

 hght neutral gray; tail of the same color, but the feathers white on 

 both webs basally, this on aU but the middle pair occupying about 

 two-thirds of their length ; terminal portion of outermost rectrices all 

 but the very tip, and most extensively on outer web, dark quaker 

 drab, rather glaucous; wings of same gray as back, the outer webs of 

 secondaries darker, somewhat brownish, the primaries also darker, the 

 outer quiUs fuscous black; inner webs of greater coverts and of most 

 of secondaries, a narrow margin on inner webs of inner primaries, a 

 broad margin on inner webs of few outer primaries, and bases of 

 all, white; tliis white pattern extends on outermost primary over 

 the inner half to two-thirds or more of inner vane, and reaches 

 nearly to the tip, leaving a broad band of fuscous black, about 4 to 6 

 mm. wide next the shaft ; on the second and third quills it is somewhat 

 narrower, and ends in a wedge some 55 or 60 mm. from the tip of the 

 feather; sides of head and neck, together with entire lower parts, 

 including the hnings of wings, white, but an ante-orbital spot, an 

 orbital ring, and the post-ocular area black, flecked with white. 



Measurements.— Wing, 303-327 (average, 315.9 ^) mm.; tail, 137.5- 

 168 (153.6); exposed culmen, 54-60.5 (57); tarsus, 25-28 (26.7)2. 

 Wing, 335.3 



Geographical distribution. — The southern and southeastern parts 

 of the Philippine Islands. Recorded from the following islands. 

 Mindanao, Pata, Sulu, Tawi Tawi, islets off Sibutu, Siquijor," Negros,* 

 Cebu,* Bohol,* Leyte,* and Samar." 



It is with considerable hesitation that I venture to name another 

 subspecies in this much-divided species, but there seems to be no 

 other satisfactory disposition to be made of the birds from the south- 

 ern Philippme Islands. They are clearly not referable to Thalasseus 

 hergii cristatus; and to place them under Thalasseus hergii peleca- 

 noides is, on account of their very inferior size, almost as much out 

 of the way. These Phihppine birds really combine the smaU size of 



1 Some of those specimens are in somewhat worn plumage; consequently the real average wing measure- 

 ment should be slightly greater than here given. 



2 Nine specimens, from the Philippine Islands. 

 ' One specimen, measured by Stresemaim. 



* No specimens examined from this island, but Thalasseus hergii halodramus is the probable form occurring 

 here. 



