In size it is a little larger than the Whiskered Bat and the Common Bat, but smaller than Leisler's Bat. The head and body measure about two inches, the tail an inch and a quarter, the ear half an inch; the wing expanse is about nine inches. The foreleg and foot are conspicuously large. The ear has a rounded tip, and a shallow concavity on the upper part of the hind margin; the lance-shaped tragus is about half the length of the ear. The spur or calcar of the foot extends three-fourths of the distance between the foot and the tail. The last two joints of the latter usually extend beyond the membrane. For its daytime rest it retires to crevices in trees, walls, caves or roofs, often in numbers, but its resorts have not the evil smell that such places frequently give off. It has a low soft chirp, less shrill than the cry of the Common Bat. In hibernation--which extends from the end of September to about the middle of April--it is no longer sociable, but hangs alone in some dark cave. There is a single young one, born in June or July. Its range extends from Ireland to Asia, and from the Mediterranean to central Norway. [Illustration: _Pl. 24._ _D 42._ *Serotine Bat.* Vespertilio serotinus.] [Illustration: _Pl. 25._ _D 43._ *Common Bat.* Alighting on branch.] *Common Bat* (_Vespertilio pipistrellus_, Schreber) The Common Bat is in a general sense familiar to everybody, for it may be seen in the evenings flying everywhere, even in the streets of crowded cities. Its British distribution extends from the South of England to Scotland and the Hebrides and westward to Ireland. Its wider range includes Europe and parts of Asia. It is the smallest of the British Bats. In spite of its small size--the head and body measure little more than an inch and a half--the Common Bat is of robust build, and it has a wing expanse of over eight inches. It has a flat broad head with a blunt muzzle and wide mouth. The short, broad ears are somewhat triangular with blunt tips. The erect, slightly incurved tragus has a rounded tip which does not reach quite to half the height of the ear. There are glandular swellings on the muzzle between the nostril and the small, but rather prominent eye. The tail is little over an inch in length, and the legs also are short. The last joint of the tail is free from the membrane and prehensile, and the Bat makes use of it as a support in crawling up or down. The spur reaches more than halfway to the tail. The narrow wing is attached to the middle of the sole of the foot. The somewhat silky fur is a reddish-brown on the upper parts, slightly paler beneath. The wing membrane and the ears are blackish.