Family VESPERTILIONIDAE 71 



with which austroriparius might be confused are brown or 

 black. 



Length measurements: head and body about 2}/^ inches (53-55 

 mm.) ; tail 1 1/^-1^ inches (28-40 mm.) ; over-all Z\^-2>yi 

 inches (81-95 mm.) ; hind foot about Y% inch (10-11 mm.) ; ear 

 1/2-^8 inch (13-15 mm.). 



The skull is long, slender, rounded behind, has a slight sagit- 

 tal crest, and attains a maximum length of 14.0-15.5 mm. 

 (about y% inch). Dental formula: I 2/3, C 1/1, Pm 3/3, M 3/3. 



The southeastern bat is difficult to distinguish from related 

 species unless specimens are available for comparison. The best 

 distinguishing characters are woolly fur, grayish brown back, 

 pale gray or white belly, and large feet, each 10-11 mm. in 

 length. 



Life History. — Little information about the life history of 

 the southeastern bat is available. In Illinois, this bat is known 

 to spend the \\inter months in caves and mines in the southern 

 part of the state. Bats of this species characteristically hiber- 

 nate in large, dense clusters. 



Distribution. — The southeastern bat is known in Illinois 

 only from caves and mines in Alexander and Hardin counties. 

 Specimens have not been found in summer, and it is not known 

 how common or widespread the species is in this state. The sub- 

 species in Illinois is Alyotis austroriparius mumfordi Rice. The 

 range of the species is poorly known, but specimens have been 

 taken in southwestern Indiana, west-central Arkansas, Louisi- 

 ana, Georgia, and Florida, as well as southern Illinois, fig. 50. 



MYOTIS GRISESCENS Howell 

 Gray Bat 



Description. — The gray bat, which is larger than the little 

 brown bat, is the only species of Myotis having a forearm 42 

 mm. or more in length. The attachment of the wing membrane 

 extends on the leg only as far as the ankle or tarsus. The fur is 

 velvety, and each hair is of the same gray color from base to 

 tip. 



Length measurements: head and body 2-2i4 inches (51-57 

 mm.) ; tail ly^-^H inches (33-44 mm.) ; over-all '^]/i-A inches 

 (84-101 mm.); hind foot Y^-Yi inch (10-12 mm.); ear about 

 y^ inch (15-16 mm.). 



