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VERTEBRATE ANIMALS OF THE UNITED STATES 



membrane. The thumb is not included in the wing membrane. The 

 foot has 5 digits; a long spur extends from the heel along the base of 

 the interfemoral membrane. The ear is large and bears an elongated 

 lobe in its concavity called the tragus (Fig. 148). In many families, 

 at the end of the snout and surrounding the nostrils is a series of more 

 or less complicated membranes called the nose-leaf (Fig. 148). The 

 mammae are thoracic in position and number i or 2 pairs. The sternum 

 bears a keel. 



The order contains about 900 species, grouped in 2 suborders, one 

 of which, the Megachiroptera, or the frugivorous flying foxes of India 

 and Australia, is not represented in this country. 



Suborder Microchiroptera. — Bats 

 with a short snout, large ears and 

 multicuspid molar teeth: 16 families and 

 about 600 species, 3 families and about 

 30 species occurring in the United States. 

 Bats are nocturnal animals, which feed 

 mostly on beetles, mosquitoes and other 

 night-flying insects, which they chew 

 before swallowing. Some species are, 

 however, frugivorous and some sang- 

 uivorous. The female of most species 

 bears one or two at a birth, which she 

 may carry about with her, clinging to her body until they are old 

 enough to be left in some safe place. Bats spend the day in caves 

 and other dark places, hanging head downward by the hind feet. 

 In the winter they hibernate or migrate. 



Key to the United States Families of the Microchiroptera 



ai Third finger with 3 phalanges; nose-leaf present; only in the 



extreme south i. Pliylloslomidce. 



a2 Third finger with 2 phalanges; nose-leaf absent. 



bi Ear with tragus; all United States bats, with a few excep- 

 tions 2. V espertilionidce. 



hi Ear without tragus; in the extreme southwest 3. Molossidcc. 



Family i. Phyllostomidae. — American leaf-nosed or vampire bats. 

 Nose usually with a nose-leaf; tragus present; wing membrane reaching 

 to the ankle; tail usually long, extending beyond the interfemoral 

 membrane; lower lip cleft: about 50 genera, all South and Central 

 American, 3 species occurring along the southern border of the United 

 States. The family includes the large fruit-eating vampire of South 



Fig. 148. — Head of Microlus califor- 

 nicus: i, tragus; 2, nose-leaf (from 

 Allen). 



