and the index one. There is an incomplete fibula. The tail may be
either long or short. Generally the dentition is _i._ 2/2, _c._ 1/1,
_p._ 2/3, _m._ 3/3.

[Illustration: FIG. 10.--Head of Blainville's Vampire (_Mormops
blainvillei_). From Dobson.]

All the bats of this family may be readily recognized by the presence
of a well-developed third phalange in the middle finger, associated
either with a distinct nose-leaf, or with central upper incisors, or
with both. Unlike the _Rhinolophidae_, their eyes are generally large
and the tragus is well developed, maintaining almost the same form
throughout the species, however much the other parts of the body may
vary. Their fur is of a dull colour, and the face and back are often
marked with white streaks. A few species, probably all those with the
tail and interfemoral membrane well developed, feed principally on
insects, while the greater number of the species of the groups
_Vampyreae_ and _Glossophageae_ appear to live on a mixed diet of
insects and fruits, and the _Desmodonteae_, of which two species are
known, are true blood-suckers, and have their teeth and intestinal
tract specially modified in accordance with their habits. The group is
practically limited to the tropical and subtropical parts of Central
and South America, although one species of _Otopterus_ reaches
California. In the first subfamily, _Mormopsinae_ (_Lobostominae_),
the nostrils open by simple apertures at the extremity of the muzzle
in front, not margined by a distinct nose-leaf; while, in
compensation, the chin is furnished with expanded leaf-like
appendages. The tail is short. It includes two genera. In
_Chilonycteris_ the crown of the head is moderately elevated above the
face-line, and the basi-cranial axis is almost in the same plane as
the facial, while in _Mormops_ (fig. 10) the crown of the head is
greatly elevated above the face-line, and the basi-cranial axis is
nearly at right angles to the facial; _i._ 2/2, _p._ 2/3, in both
genera. As regards the species of _Chilonycteris_, the most striking
feature is the occurrence of a rufous and a dark brown phase in each.
In some the two phases are very marked, but in others they are
connected by intermediate shades. Here may be mentioned the two
species of tropical American hare-lipped bats, forming the genus
_Noctilio_, which presents characters common to this and the following