362 C. H. TURNER 



a few seconds, the wasps usually became quiet; but when it 

 followed ruby (Exp. 22) the wasps were stimulated to activity. 

 In about 85 per cent of the experiments the responses were as 

 stated above; but the exceptions were too numerous to permit 

 one to predict, with certainty, the response that will follow the 

 use of a certain colored light as a stimulus. I have known the 

 blue to follow a bright white light (Exp. 20) without causing 

 the wasps to become inactive, and I have also noticed other 

 incongruous responses. 



When exposed continuously to an activity-inducing stimulus, 

 Trypoxylon albotarsus exhibited a rhythm in its behavior. It 

 would be active for a while, take a rest and then become active 

 again. The cause of this rhythm was not apparent. One who 

 has watched these wasps in the open could hardly believe the 

 rest due to fatigue; for the amount of exertion and the time of 

 activity were much less than what is exhibited by wasps afield. 

 The pause may simply have been the result of the failure to 

 find a means of escape. That the wasps were trying to escape 

 is evident; for, when the wasps were actively flying about, no 

 opening could be made anywhere in the cage without one or 

 more wasps escaping or trying to escape. 



