26 BULLETIN 98, UNITED STATES NATIONAL MUSEUM. 
less convex, the culmen much more sharply ridged—almost as in 
Alcedo and Alcyone—and the gonys more decidedly keeled. The 
three species above included should therefore be called: 
Therosa argentata (Tweeddale). 
Therosa solitaria (Temminck). 
Therosa cyanopectus (Lafresnaye). 
Family MICROPODIDAE. 
#MICROPUS SUBFURCATUS (Blyth). 
Cypselus subfurcatus Burrs, Journ. Asiat. Soc. Bengal, vol. 18, August, 1849, 
p. 807 (Malay Peninsula). 
Recorded from the Anamba Islands by Mr. C. B. Kloss.! 
COLLOCALIA LOWI (Sharpe). 
Cypselus lowi SHarpE, Proc. Zool. Soc. Lond., 1879, p. 333 (Labuan Island, 
northern Borneo). 
One adult male from Pulo Riabu, August 22, 1900. Length, 133.5 
mm.; wing, 134mm. ‘‘Shot out of a flock of nearly a hundred that 
were hawking along the beach in the evening.” ‘The present example 
has the tail distinctly though not deeply emarginate; but this can 
be regarded as scarcely more than an individual peculiarity. Indeed, 
the shape of the tail, as a character used to distinguish Collocalia lows 
from Collocalia whiteheadi, is of doubtful value, for some specimens of 
the latter have the tail almost square, while Collocalia lowi sometimes 
shows distinct emargination. 
Mr. Erwin Stresemann has recently described? as a subspecies 
of Collocalia lowi the form of Collocalia whiteheadi from Palawan 
Island which the present writer some years ago indicated as possibly 
separable. This is a bird with unfeathered tarsi, like Collocaha 
whiteheadi, and clearly is a subspecies of that species, not of Collocaha 
lout, with which it has nothing to do, and should, therefore, stand 
as Collocalia whiteheadi palawanensis. These two species, Collocaha 
lowi and Collocalia whiteheadi, are very similar in coloration, as, 
indeed, are so many of the other distinct species of this difficult 
genus, but Collocalia lowi is somewhat darker below than both 
Collocalia whiteheadi whiteheadi and Collocalia whiteheadi palawa- 
nensis, with more distinct dark shaft streaks and more uniform 
coloration, the throat not being noticeably lighter than the breast 
and abdomen, as is the case in both forms of Collocala whitehead. 
In fact, the most satisfactory means of distinguishing these two 
species is the difference in the feathering of the tarsi. Thus, to 
consider Collocalia whiteheadi, a bird with unfeathered tarsi, a sub- 
Se ee eS Lt Ee ee 
1 Journ. Straits Branch Roy. Asiatic Soc., No. 41, January, 1904, p. 79. 
2 Collocalia lowi palawanensis Stresemann, Verhandl. Ornith. Gesells. Bayern, vol. 12, May 15, 1914, 
p- 10. 
