336 Journal of Comparative Neurology and Psychology. 



lamp is kept over towards the blind side they may be made to 

 perform circus movernents in a direction opposite to that in which 

 they would otherwise tend to go. 



B 



J^i^. J. Tracings of successive paths towards the light taken by a Notanecta, 

 which had the left eye blackened over. After a number of other trials the speci- 

 men came to travel towards the light in nearly a straight line. 



i^. Fortnation of Habits of Turning. In working with 

 Ranatras I have several times noticed what appeared to be a 

 tendency to fall into habits of action, and I was naturally led to 

 test the matter further by experiment. A Ranatra with its 

 right eye blackened over was placed so that its head pointed 

 directly away from a lamp three feet behind 

 its body. As was to be expected, the Rana- 

 tra turned around to the left and went to the 

 light. It was then picked up and placed in 

 the same position ten successive times. In 

 each trial it turned to the left and went up to 

 the light as at first. In these and all subse- 

 quent trials the insect, when picked up, was 

 turned alternately to the right and to the left 

 before it was put down again. In this way 

 the possibility that the results might be due 

 A to compensatory motions was eliminated. 

 f^g- 6. After the first ten trials the insect was placed 



obliquely (at an angle of 45°) to the rays with its right 

 side towards the light (position B in Fig. 6). In each of 

 the ten trials that were made the insect turned towards the right 

 or bUnd side, and went to the light. It was then placed 



C «- 



