REACTIONS TO LIGHT IN VANESSA ANTIOPA 409 



stimuli may be neutralized by their simultaneous action on the 

 organism. 



These experiments in non-directive light of different intensi- 

 ties show conclusively that there is no relation between the degree 

 of curvature of circus movements and the intensity of the light 

 above certain very low limits. They thus support most strongly 

 the conclusion reached before, that orientation in Vanessa is 

 not dependent upon the relative amount of light energy received 

 by the two retinas. 



Fig. 19 Reproduction of trails made in non-directive light of higli intensity, 

 460 mc, by butterfly 10/13-a (left eye blackened) . Compare the preceding figure 

 with this one and note that in light of high intensity the animal does not move 

 in courses with a smaller degree of curvature than it does in light of low intensity^ 

 thus exhibiting reactions not in accordance with Loeb's theory of orientation. 



In addition these results contradict an apparently possible 

 explanation of the reactions in the horizontal beam of light. 

 Superficially it would seem that these reactions may be due 

 simply to a balanced effect of two stimuli acting unilaterally, 

 one, light, acting continuously and tending to cause movement 

 toward the functional eye, and the other, the covering of the 



THE JOURNAL OF EXPERIMENTAL ZOOI-OGV, VOL. 20, NO. 3 



