Family VESPERTILIONIDAE 



75 



Fig. 53. — biiver-haired bat. 



part of the state, but most of them migrate farther south. An 

 inhabitant of woodlands, fig. 1, this bat lives alone (not in colo- 

 nies) in the hollows of trees, beneath bark, or under leaves. It 

 often pursues insects near the tops of trees. It may occasionally 

 breed in Illinois, particularly in the northern part. An adult 

 female usually bears two young, in June or July, which must 

 develop rapidly to be prepared for the strenuous fall migration 

 southward. 



Distribution. — The silver-haired bat is moderately common 

 throughout Illinois during the summer months. About the last 

 week of April it is fairly common in the vicinity of Urbana. No 

 subspecies is recognized. The species occurs from Nova Scotia 

 and southern Quebec to southern Alaska and southward to 

 central California, southern Arizona, southern Kansas, southern 

 Alabama, and southern South Carolina. 



PIPISTRELLUS SUBFLAVUS (Cuvier) 



Eastern Pipistrel 



Description. — The eastern pipistrel, fig. 54, is the smallest 

 Illinois bat. Its fur is yellowish brown to drab brown, lighter 

 on the under parts of the body, and the wings are dark reddish 

 brown. Each ear has a blunt but straight tragus. This pipistrel 

 resembles the red bat but is paler and much smaller. 



