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Bulletin American Museum of Natural History. [Vol. XXXVII, 



muzzle, no nose-leaves, relatively small eyes and ears, the latter placed on 

 the side of the head, with slender, nearly straight tragus. The wings are 

 fairly broad, with two phalanges in the middle finger. The color of their 

 membranes may be either dark, transparent, or even vividly colored. 

 The interfemoral membrane is especially wide and supported to its very 

 tip by the tail -vertebrae. Most of them feed on very small insects, and some, 

 like Pipistrellus, take mosquitos. Mimetillus, having short appressed hair 

 and narrow wings like the Molossidse, is to be noted as an exception (Fig. 22). 



The Molossidae are rather common. They have short appressed body- 

 hair with a peculiar velvet-like luster in life. The head is rather thick and 

 clumsy, the muzzle obliquely truncate, the small nostrils usually terminate in 

 a pad, but without nose-leaves. The ears may be erect and separated (Plate 

 LIII, Fig. 2) but more often join across the forehead and project beyond the 

 tiny eyes (Plate LIII, Fig. 2). Their posterior borders extend far down on 

 the cheeks and the tragus is small. The wings are very narrow, their tips 

 folding underneath (Fig. 25) or above, the membranes dark, light or trans- 

 parent. Typical of this family is a separate narrow band of fur near the 

 inner edge of the wing-membrane on its lower surface, extending from the 

 armpit to the thigh and usually of the same color as the belly. The tail 

 projects considerably beyond the edge of the interfemoral membrane, its 

 skin thick, fitting loosely over the vertebra? (Fig. 17, D). The heavy, short 

 feet are free from the membranes; but the spoon-hairs on the two outer toes 

 are characteristic (Fig. 26) ; those on the wrinkled lips are often very minute. 

 Their flight is extremely swift and rather continuous, with turns less rapid 

 than the Emballonurida?. They generally feed on hard-shelled insects. 



