Figure 2. — Ear (E) and tragus length (TR) measurements. 



not be reliable for identifying juveniles. Bats can be 

 placed reliably in juvenile or adult age classes by 

 examining the extent of epiphyseal-diaphyseal fusion in 

 the finger joints (Anthony 1988). Cartilaginous plates are 

 not apparent in the finger joints of adults, which consists 

 of a single, knobby protuberance (Fig. 1). Cartilaginous 

 plates are apparent in juvenile finger joints, which consist 

 of two protuberances with a slight taper between, or a 

 single protuberance that is much longer and more tapered 

 at both ends than that in adult joints (Fig. 1). The most 

 effective way to observe the cartilaginous plates is by 

 backlighting the wing and looking for semitransparent 

 sections in the joints of the phalanges. 



Key to Bat Skins 



1 . a. One-third or more of the tail extends beyond 

 uropatagium (Fig. 3a) — Brazilian free-tailed bat 

 ( Tadarida brasiliensis) 



b. Tail does not extend beyond uropatagium or only 

 slightly (Fig. 3b) — 2 



2. a. At least one-third of the dorsal surface of 

 uropatagium furred — 3 



b. Dorsal surface of uropatagium not furred or slightly 

 furred at the junction with the body — 7 



3. a. Pelage black; tips of hairs frosted with white — 4 

 b. Pelage dark red, mahogany, or yellow — 5 



Figure 3. — Contrast between the tail and 

 uropatagium of the Brazilian free-tailed bat {Tadarida 

 brasiliensis) and the other 1 5 species of bats that are 

 found in the Southeastern and Mid-Atlantic regions. 

 The tail of the former extends beyond the posterior 

 margin of the uropatagium (A); the tails of the other 

 15 bat species are enclosed in the uropatagium (B). 



4. a. Total length more than 120 mm; uropatagium 

 heavily furred throughout; ear white or yellow with 

 black rim — hoary bat [Lasinrus cinereus) 



b. Total length less than 1 1 5 mm; posterior one-third 

 of uropatagium bare; ear solid black — silver-haired bat 

 {Lasionycteris noctivagans) 



5. a. White shoulder patch absent, yellow coloration, 

 frosting absent — northern yellow bat {Lasiiirus 

 intermedins) 



4 



