SENSORY ADAPTATIONS OF BATS. 179 



States that a hairy-armed bat, Vesperugo leisleri {Ptcrygistes 

 leislei'i), learned to come for food on hearing a pair of scissors 

 cHcked together. 



For studying place associations the following method was used : 

 The bats were kept in cages in the dark room as previously de- 

 scribed. For the experiments they were taken into a well lighted 

 room and placed in a small experimental cage made of wire cloth, 

 the sides being of one fourth inch mesh and the top, bottom and 

 ends of one eighth inch mesh. The dimensions were 12 by 13 

 by 27 inches. On one side was cut a hole seven inches square. 

 This opening was closed with a door made of the same material 

 as the side, and overlapping the edges an inch all around. It 

 \vas fastened with a wooden latch on the outside. A piece of 

 white cloth, three inches square, was fastened inside the cage, 

 near the upper left corner of the door. 



The bat to be used in the experiment was placed on the floor 

 of the cage near the middle. All of its movements were carefully 

 recorded during the whole time it was in the cage. As soon as 

 it touched the cloth while following its natural tendency to ex- 

 plore every part of the cage, the door was opened and a meal 

 worm was offered it with a pair of forceps. 



Animals that had never been handled were usually frightened 

 away by thrusting the hand toward them and moreover they did 

 not know how to eat the meal worms. Therefore it was neces- 

 sary to use bats that had been in captivity for some time and had 

 learned to eat the food offered them. 



As soon as the animal under observation had eaten the food 

 given it, it was again placed on the bottom of the cage and given 

 another chance to come to the same place for a worm. The 

 time required was carefully noted and also the movements of the 

 animal which did not result in bringing it nearer to the food. 



The curves given by Porter ('04) for similar observations on 

 English sparrows, and Kinnaman ('02) for monkeys, are fairly uni- 

 form after the animal had found the food once or twice. The 

 animals used by these observers apparently responded in about 

 the same way to the same stimulus in all instances where there 

 was no disturbing factor. The reactions of a bat are much less 

 constant. When placed in the experimental cage it sometimes 



