Descriptions of East Asiatic Mammals 83 
Myotis mystacinus, with forearm 1% inches. A large number of 
closely related forms are known, among them the species 
M. siligorensis, with greatly domed braincase, from the Hima- 
layas, Siam, Tonkin, Fukien. Other continental species of Bats 
of this subgenus are sibiricns from northern Mongolia, gracilis 
from Vladivostok, muricola from Nepal and Laos, lobipes from 
Akyab, western Burma, altarium from Szechwan, frater from 
Fukien, latirostris and orii (if distinct from one another) from 
Formosa, deignani from Siam, federatus from Selangor, oreias 
from Singapore. All are small brownish Bats, distinguished 
from each other by minute characters which cannot be elaborated 
here. They are often gregarious, hiding in thatches, caves, or 
hollow trees by day and coming forth to hawk insects by night. 
The Natterer's Bats, subgenus Isotus, are a small group of 
the temperate zone, in which the length of the forearm is about 
1% inches. The ear typically is longer and narrower than in 
the Whiskered Bats. In eastern Asia the species is represented 
by M. natter eri amurensis of eastern Siberia and by M. n. 
bombinns of Japan. 
The Copper-winged Bats, subgenus Chrysopteron, with 
conspicuously bicolored red and slate wings, occur in south- 
eastern Asia, the Indo- Australian Archipelago, and Africa. The 
only forms in the eastern Asiatic mainland areas are formosus 
from Nepal (which may well equal aura tits from Darjiling and 
Assam), flavus from Formosa, rufoniger from Shanghai, and 
chofukusei from Korea. The geographical pattern suggested by 
these localities suggests for Chrysopteron a coastal type of dis- 
tribution. 
These are by far the most interestingly colored species of the 
genus, the pattern of the wings being somewhat similar to that 
of the Painted Trumpet-eared Bat, Kerivoida picta. 
The True Mouse-ear Bats, subgenus Myotis, are the larg- 
est of the Mouse-ears and inhabit the mild temperate zone of 
the Old World. The length of the forearm varies from 2% to 
2% inches. The color is rather dark brownish gray, slightly 
