Fomily VESPERTILIONIDAE 73 



Distribution. — Keen's bat, distributed the length and breadth 

 of Illinois, may be common in some places, but the records of 

 the species for this state are surprisingly few. The subspecies 

 in Illinois is Myotis keenii septentrionalis (Trouessart). The 

 range of the species is discontinuous, one population occurring 

 in an area extending from Newfoundland to western North 

 Dakota and southward to central Arkansas and western Flor- 

 ida and another population occurring in western British Colum- 

 bia and western Washington. 



MYOTIS SODALIS Miller & Allen 

 Indiana Bat 



Description. — The Indiana bat is similar to the little brown 

 bat in body and skull size. The fur of the back is composed of 

 hairs that are blackish brown at bases, dull pinkish gray at 

 tips, rather than a bronzy brown as in the little brown bat. The 

 pinkish gray is conspicuous on the fur of the under side. The 

 Indiana bat differs from the little brown bat in that the hind 

 foot is smaller (the foot of the latter is 10-11 mm. in length), 

 the hairs on the toes are much shorter and less conspicuous, and 

 along the calcar is a keel, or flap of skin, as shown in fig. 39. 

 The keel is most evident in live animals; frequently, in dry study 

 skins it cannot be discerned. 



Length measurements: head and body lJ/^-1^ inches (40-48 

 mm.) ; tail \]/i-\yi inches (30-42 mm.) ; over-all 2^-3i/^ 

 inches (70-90 mm.) ; hind foot ^ inch (7-9 mm.) ; ear from 

 notch y^-y^ inch (10-15 mm.). 



The skull differs from that of the little brown bat in such 

 small details as having a narrower braincase (less than 7.4 

 mm., about 14 inch) and narrower interorbital breadth (less 

 than 4.0 mm., about 1 « inch). The number of teeth is the same 

 as in other species of Myotis. Dental formula: I 2/3, C 1/1, 

 Pm 3/3, M 3/3. 



Life History. — The Indiana bat usually hibernates in caves. 

 In these places individuals hang in compact clusters, often near 

 groups of the little brown bat. Hundreds of them are neatly 

 packed together in each cluster. Little is known about the colo- 

 nies after they leave the hibernating caves. However, some In- 

 diana bats may spend the "summer" in small colonies in other 

 caves. 



