Of the numerous creatures which attract our admiration, or excite our fears, the greater part display their appetites, or develope their instincts, during the day time only; especially--with few exceptions--all those remarkable for beauty of plumage, and vocal melody. Predacious animals are chiefly distinguished for their nocturnal habits; and ideas of rapine, terror and blood, are ever associated with the tiger, the hyena, and the wolf. Among the feathered tribes, the _owl_ and the _bat_, also companions of darkness, are shunned by many, as horrible objects, and full of ill-omen. Haunted castles, ruined battlements, and noisome caverns, are the chosen abodes of these noctural maurauders, and it is to such associations that these animals are indebted for the unamiable character they have obtained. The prejudices conceived against that portion of these animals, with which we are familiar, are founded entirely upon these their habits; for small quadrupeds, reptiles and fish, constitute the food of the first, whilst insects and fruit suffice for the other. It is at the close of the day, when the hum of nature is beginning to subside, that the patient _bat_ steals from his dark retreat, and spreads his leathery wings in search of his food. [Illustration] The new species of this little flying quadruped, which we are now about to notice, belongs to a very large and respectable family. In the days of Linnaeus, they all--from their appearance at twilight--went by the family name of _Vespertilio_. They further belong to the order _Carnivora_, their teeth being constructed for masticating flesh; though some--and in this they resemble ourselves--are also fond of fruit. In one important point, the whole race has a common character, in their organ of flight. The bones of the fingers are extremely elongated, and united by a membrane, which is continued down the side of the body; and extending on the leg as far as the tarsus, also unites the legs and tail. Agreeing so universally in this particular, they form a very natural family, under the appropriate term. Cheiroptera, constructed from two Greek words, signifying _hand and wing_. The vespertilio are again divided into GENERA and _Species_,--divisions which are grounded on certain peculiarities of dental structure, and various developements of the brachial, digital, and interfemoral appendages, with other modifications of the organs of progression. These genera include species which are discovered in every habitable part of the globe, of various magnitudes, from the size of a half grown cat, to that of a half grown mouse. Of this numerous family only three genera, of modern authors, inhabit the United States, viz. RHINOPOMA, VESPERTILIO, and TAPHOZOUS. Seven species, exclusive of the present, are all that have been hitherto discovered in North America.