1906.] NATURAL SCIENCES OF PHILADELPHIA. 207 



Measurements of Collocalia linchi affinis are as below : 



Collocalia linchi elachyptera subsp. nov. 



Chars, subsp. — Similar to Collocalia linchi affinis, but more greenish 

 on all the upper parts, particularly on back, wings, and tail. 



Geographical distribution. — Islands of the Mergui Archipelago. 



Description.— Type, adult male. No. 173,028, U. S. N. M.; Bentinck 

 Island, Mergui Archipelago, March 9, 1900; Dr. W. L. Abbott. Upper 

 parts deep metallic green, with an appreciable bluish purple tinge, 

 particularly on the upper tail-coverts ; tail the same, but more bluish ; 

 wings fuscous, the exposed portion of quills and primary coverts with 

 a dull metallic purplish sheen, the other superior coverts like the back; 

 lores dark brown, the feathers with pure white bases; rest of sides of 

 head and neck, with chin, throat, and breast, dull brownish slate color, 

 the feathers of the throat and upper breast with pale grayish or whitish 

 tips; lower breast, sides, and flanks brownish slate with a slight metallic 

 greenish sheen, the feathers all broadly margined with white which 

 much obscures the darker color ; middle of abdomen white with shaft 

 markings of dusky; exposed portions of lower tail-coverts dark metallic 

 greenish, the shortest brownish, all but the longest broadly bordered 

 with white; lining of wing dark brown, glossed with metallic green. 

 "Bill black; iris dark brown; feet dark fleshy brown." 



This race is of course intermediate between Collocalia linchi affinis, 

 from the Andaman Islands, and Collocalia I. isonota,'"' from the Philip- 

 pines; but the differences that characterize it are readily appreciable 

 in a series, as well as in a large proportion of individual speci- 

 mens, and seem, particularly when its isolated range is taken into 

 account, quite sufficient for its recognition by name. It is readily dis- 

 tinguishable from true linchi by reason of its much inferior dimensions 



« Postea. 



