204 PROCEEDINGS OF THE ACADEMY OF [April, 



Wing, 103-107; tail, 41-43; exposed ciilmen, 3.5-4; tarsus, 7.5-9 mm. 



Ty-pe locality.— Cehu Island, Philippine Islands. 



Geographical distribution. — Philippine Islands. 



This interesting bird, supposed until recently to be very rare, bids 

 fair to be found distributed pretty generally throughout the Philip- 

 pine archipelago. Up to the present time it has been ascertained to 

 occur on the following islands: Cebu, Masjjate, Luzon (McGregor), 

 Mind or o, Calayan, and Sibuyan. 



It scarcely needs close comparison with any other member of the 

 genus except Collocalia linchi, and to distinguish it from this there 

 should be no difficulty. The white margins of the brownish gray feath- 

 ers of the throat and breast are usually broad and conspicuous, but 

 occasionally in even unworn specimens are almost obsolete. 



Collocalia linchi linchi Horsfield and Moore. 



1 Hemiprocne fucirora Streubel, Lsis, 1848, p. 369 (East Indies). 

 Collocalia linchi Horsfield and Moore, Cat. Birds Mus. East Ind. Comp., I, 

 1854, p. 100 (Java). 



Chars, subsp. — Very much hke Collocalia marginata, but feathers of 

 the rump without white margins ; upper surface usually more brightly 

 colored; throat and breast generally with less conspicuous white 

 edgings. 



Type locality. — Java. 



Geographical distribution. — Java ; Lombok ; Kangean Islands ; Suma- 

 tra, including the islands along its western coast; Singapore, and the 

 southern part of the Malay Peninsula; Borneo(?). 



This species is shown by the considerable amount of material from 

 various parts of its range now in the United States National Museum 

 to be divisible into several recognizable races which are diagnosed 

 below. Aside from the evident geographical variation there are some 

 differences that seem to be due to wear of the plumage and to obtain 

 alike in all the forms. The color of the upper parts changes little 

 through sex, age, or season, although there is a normal but not very 

 considerable amount of individual variation. The deep gray of the 

 anterior lower parts is decidedly more brownish when the feathers 

 become old ; and the white or whitish margins that in fresh plumage 

 are often very conspicuous on throat, breast, and under wing-coverts 

 sometimes almost entirely disappear through abrasion. Likewise the 

 broadly w^hite edgings of sides, flanks, and lower breast wear off and 

 ultimately allow much of the slate gray bases of the feathers to show, 

 in this way decidedly darkening the general appearance of the parts. 



This form of Collocalia linchi, as compared with the other sub- 



