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



sure to find insectivorous bats; but on the level and barren plains, one is 

 just as sure to find very few. They sometimes shun trees or other places 

 infested by ants, the winged individuals of which they readily devour, and 

 yet they inhabit trees housing termites, which seem not to molest them. 

 Far from minding the company of flying-squirrels (Anomalurus and Idiurus) 

 or of geckoes (Hemidadylus), they are often found living with these. 



Those with gregarious tendencies have so many traits in common that 

 one looks in vain for differences in their behavior caused by diversity of 

 environment. On the borders of the dry regions of the Sudan or in the 

 moisture-laden rain-forest their habits seem in all essentials the same. 

 They may flock together, sometimes only half a dozen in a small knot-hole, 

 or several hundred in a large hollow tree or rocky cleft. Caves may attract 

 thousands but all these colonies are made up habitually of members of but 

 one species. Night after night they return to their accustomed roosts, 

 which they do not abandon even when frequent raids made upon them by 

 the natives have thinned out their numbers. Large, juicy lumps of fat, 

 deposited in and about their abdominal cavity, stimulate the natives to kill 

 all they can. 



Native traditions, and still more the thick layers of guano in some of the 

 caves and beneath the rocky clefts, would tend to justify the belief that 

 many of them die where they are born. This is fully confirmed by the 

 records of Rhinopoma microphyllum living by the thousands in the Pyra- 

 mids. Anderson (Zoology of Egypt, Mammalia, 1902, p. 148) offers proof 

 of their having lived and bred there for nearly 3000 years without showing 

 any perceptible changes. 



The species of Molossida? which we found have a relatively limited range. 

 Among them gregariousness is the ideal mode of life and they huddle to- 

 gether in lumps. Often they exhale a disagreeable odor that might possibly 

 help them to find each other more easily. Our observations would tend to 

 show that they probably are polygamous, although data from other coun- 

 tries indicate that males and females of this family form separate colonies, 

 at least at certain seasons. The Emballonuridse show stronger propensities 

 for society than the Rhinolophidse. Of the Vespertilionida? only a few 

 species form really large colonies. Houses and similar structures which 

 offer the same advantages as their natural abodes are readily invaded by 

 such bats. 



All these bats that live in colonies and rest with feet and wings against 

 the walls (p. 549) and climb over each other, have short smooth appressed, 

 rather lustrous hair. With all the Molossidse, at least, we find this to be 

 true. Among the Emballonuridse, Saccolaimus peli and also Taphozous 

 mauritianus are good examples, though they rest singly. Even Eidolon 



