BATS IX RELATION TO GUAXO AND INSECTS 



tails, short, wide ears pointing forward over the eyes like a hat rim, 

 and short velvety fur. (Figs. 1 and 2.) Individually these bats are 

 cleanly animals, but they have the extremely strong musky odor 

 peculiar to the group. This permeates the air of every cave or 

 house which they occupy in any numbers. In some houses where 

 they are present in large numbers it becomes almost unbearably 

 strong, and its offensiveness is increased by the added pungent odor 



Fig. 2. — Mexican free-tailed bat (Tadarida mexicana), natural size (see also 



figure 1) 



of ammonia from their excrement. In many houses where bats are 

 found among the tiles of the roofs of porches and in crevices over 

 the lintels of doorways and similar places, the odor pervading the 

 premises often advertises their presence to anyone approaching. 



In the numerous reports on bat guanos and their chemical com- 

 ponents and value as fertilizer, samples have been listed from 

 the caves of Africa, India, China, South America, the West Indies, 



