TESPERUGO. 301 



rounded lobe or antitragiis, the innev margin is tm-ned inA\ards 

 near the base and generally forms a rounded edge termed the basal 

 lobe. Tragus generally short and obtuse, the outer margin moi*e 

 or less convex, the inner straight or concave. 



Muzzle in most species short and obtuse *, with pi'ominent 

 glandular swellings at the side between the eyes and nostrils, in- 

 creasing the width of the face ; the sides of the head as far back 

 as the ears, and extending upwards to above the eyes, together 

 with the terminal portion of the muzzle above from a little in front 

 of the eyes, are very thinly covered \\ ith hair. Tail shorter than 

 the head and body together ; there is a small membranous expan- 

 sion (the postcalcaneal lobe), varying much in form and develop- 

 ment, behind the cnlcaneum, and the interfemoral membrane 

 always ends posteriorly in a salient angle. AVings (except in 

 V. noctula, V. leisUri, and two Mala3'an species) from the base of 

 the toes. 



-p. . . . 2—2 1—1 2—2 1—1 3—3 mv 



Dentition: i. ^', c. j^--^ pm. .,_., or .,_3, m. g^. ihe upper 

 incisors in pairs inclined inwards and separated by a wide in-r 

 tei*val in the middle, outer incisor of each pair close to the inner 

 and parallel to it ; the inner generally the larger of the two and 

 often bifid, the outer sometimes very small (see fig. 92, p. 306). 

 First upper px'emolar minute or wanting; often, when present, 

 difiicult to detect. First lower premolar in the tooth-row, not 

 crushed in between the adjoining teeth ; its summit directed 

 slightly outwards. 



This genus of bats, which comprises more species than any 

 other, and contains the commonest and most widely spread forms, 

 is found in all extensive land areas, except those of the polar 

 regions, but is particularly well represented in the temperate and sub- 

 tropical portions of the Eastern hemisphere. All the species have a 

 rapid flight with very sudden twists and turns, and many are amongst 

 the first bats to appear in the evening and the earliest to leave 

 their winter-quarters in the spring. In the majority of the species, 

 according to Blasius, unlike other bats, the females produce two 

 young at a time ; but Dobson found one to be the rule in the 

 numerous specimens that he examined. 



On account of the number of species included, attempts have 

 been made to divide the genus, but the subgenera, with the ex- 

 ception of Ues'^croptemis^ are ill defined and more or less artificial. 

 This is especially the case ^vith the t^^■o largest subgenera, Vch- 

 lierus and Vesperiujo. The small first upper premolar, wauting 

 in the first but present in the latter, is sometimes to be distin- 

 guished from uiiiaide between the canine and the second premolar, 

 but often it can only be detected by the use of a good lens when 

 the mouth is widely opened. 



* V. annectcns difiers in this and several other characters. 



y2 



