384 



WILLIAM L. DOLLEY, JR. 



usually turns until it assumes a certain angle with the rays of 

 light, and that it then proceeds diagonally across the beam. If 

 orientation is dependent upon the relative amount of light energy 

 received by the two eyes, as demanded by the 'continuous action 

 theory,' the degree of deflection ought to be greater in high 

 illumination than in low, for if only one eye is functional, the 

 greater the intensity, the greater the difference in the amount 

 of energy received by the two eyes. This was tested by measur- 

 ing the angles of deflection in different intensities of light in each 

 one of the trials made by all of the insects. The results of some 

 of these tests are recorded in figure 9 and in table 2. 



TABLE 2 



Angles of deflection made in different intensities of light by four butterflies ivith one 



eye blackened 



