Descriptions of East Asiatic Mammals 79 
the Microchiroptera. At the same time, the small size and 
seeming uniformity among a large number of the species tend 
to obscure their very great diversity. It has been thought worth 
while to outline the families and subfamilies, with the number 
of genera in each, which will be treated in the present work. 
There exist also a number of other families, notably in the 
New World tropics. The reader can see at a glance from the pre- 
ceeding table that a very large proportion of the Insect-eating 
Bats belong to the two large families Rhinolophidae and Vesper- 
tilionidae, and to three only of the seven subfamilies composing 
them. 
the true insect-eating bats 
(family vespertilionid^e) 
When we see a Bat flit past in the dusk in the northern United 
States, the chances are overwhelmingly great that it is a member 
of this family. The word Vespertilio comes from the Latin word 
meaning "a bat." By a quirk of circumstances this generic name 
has become associated with a genus of the Old World temperate 
zone whose members are by no means the most abundant. The 
Bats more commonly seen in the north are the Brown Bats of 
the genera Myotis and Eptesicus. 
In all members of the family the tail is long — considerably 
longer than the hind legs — and the membrane connecting it with 
the legs is more or less diamond-shaped. In all five subfamilies 
but one (found only in Australia and western America), there 
is total absence of noseleaves. The ears are usually small and 
separate, but in the Long-eared Bat, Plecotus and its American 
relatives, they are very large. A number of other adaptations 
found in the Vespertilionidse will be discussed in their places. 
No very large Bats occur in this family; the forearm meas- 
ures less than 3 inches in the largest species, and quite small 
species having the length of the forearm only about 1% inches 
are numerous. Although a limited number of genera are found 
