In this section are the four families of the Vespertilionidae, Rhinolophidae, Noctilionidae, and Phyllostomidae.
Fam. 1. Vespertilionidae. - In this family are the ordinary Bats, distinguished by having a dentition very like that of the order of the Insectivorous Mammals, the molar teeth being furnished with small pointed eminences or cusps, adapted for crushing insects, and the incisors being of small size. The nose is not furnished with leaf-like appendages, and the tail is elongated, and enclosed in a large inter-femoral membrane. The species of this family are generally distributed over the temperate and warm regions of both the Old and New Worlds. About fifteen species of this family have been described as British, but of these only two are at all common. Of these two, the Pipistrelle (Vesperiilio pipistrella) is the commonest species, occurring over the whole of Britain. The long-eared Bat (Plecotus auritus) is also not uncommon, and is distinguished by its greatly elongated ears, which are confluent above the forehead. The largest British species is the Noctule (Vespertilio noctula), which measures as much as fifteen inches in expanse of wing.
Fam. 2. Rhinolophidae. - The second family of the Insectivorous Bats is that of the Rhinolophidae or Horse-shoe Bats which in most respects are very similar to the Vesperiilionidae, but are distinguished by the possession of a complex leaf-like apparatus appended to the nose. In the typical forms of the family the ears have no tragus or earlet. Of this family, two British species are known - the Greater and Lesser Horse-shoe Bats (Rhinolophus ferrum-equinum and R. hipposideros).
Most of the Horse-shoe Bats are Asiatic and African, a few being found in Australia. The genera Nycteris and Megaderma are sometimes separated to form a distinct family (Nycteridae), distinguished by having very large ears, with a well-marked tragus or earlet.
Fam. 3. Nodilionidae or Emballonuridae. - In this family are a number of Bats which are principally South American, African, and Asiatic, and which are distinguished from the Vespertilion-idae by the fact that the tail usually perforates the inter-femoral membrane at or about its middle, and the incisors are of large size.
Fam. 4. Phyllostomidae. - This is the only remaining family of the Insectivorous Bats, and comprises the well-known Vampire-bats (fig. 444, A), distinguished by having leaf-like nasal appendages, and by the fact that the ears are of small size; whereas in the preceding they are always very large (Rhinolophus), and are often confluent above the forehead (Megaderma). They are all of large size, and are natives of South America, extending northwards to Mexico and California. The Vampire-bat (Phyllosto-ma spectrum) has an expanse of wing of two feet and a half, and lives chiefly upon insects. Some species of the family have the habit of sucking the blood of sleeping animals, appearing sometimes to attack even man, though apparently never doing any substantial or lasting injury.