90 Mammals of Eastern Asia 
The Frosted or Linnaean Bats, Vespertilio murinus, are a 
tiny group of rather large Bats, deep brown in color, with the 
tips of the hairs frosted with white. In eastern Asia two forms 
are known, V. m. superans from Vladivostok, Amur, the Yang- 
tse Valley, Szechwan, Hupeh, Shansi, Hopei; and V. nameyei 
from Japan. Both have the length of the forearm 2 inches or 
slightly less. Vespertilio murinus, rapid high fliers, live in hollow 
trees and under roofs in colonies. One group of twenty speci- 
mens taken in Russia included eighteen males and two females. 
The two young are apparently born at the beginning of June, 
and begin to fly by the end of that month. The Bats hibernate 
in large groups. 
The Serotine or "Big Brown Bats," genus Eptesicus, are 
near relatives of Vespertilio but have not the frosting on the 
fur. The genus is a large one with world-wide range; it has 
been separated into a number of groups, five of which are found 
in eastern Asia. 
Eptesicus nilssonii group is represented in the East by E. n. 
velox from Vladivostok and Korea and by E. n. gobiensis from 
Mongolia. Forearm about 1% to 1% inches. The entire group 
is subtropical to northern. The original nilssonii comes from 
Sweden. Two young are born. This group is sometimes sepa- 
rated under the generic name Amblyotus. 
Eptesicus fuscus group includes the "Big Brown Bats" of the 
United States. The forearm varies from 1% to 2% inches. A 
number of Oriental races occur : andersoni in Yunnan, Fukien, 
and Chekiang, sinensis in Pekin, pollens in Kansu, and brachy- 
digitus in Korea. The European race, E. f. serotinus, is recorded 
also from Siberia (Dauria and Lakes Argun and Tari-Nor). 
Bats of the fuscus group live in hollow trees, barns, and attics, 
occasionally gregariously; they hibernate sometimes alone in 
similar localities. The course of flight is less erratic than that of 
Pipistrellus. Only one baby Bat is born at a time. 
Eptesicus demissus, a. unique chestnut-brown species, comes 
