416 WILLIAM L. DOLLEY, JR. 



in the environment exhibited alternate periods of activity and 

 i*est. Forty periods of activity were observed during the test. 

 In fifteen of the first twenty of these it attempted to turn away 

 from the illuminated eye, while in fifteen of the last twenty it 

 attempted to turn in the opposite direction. On the third day 

 it attempted to turn toward the illuminated eye uniformly. 



In table 9 the results secured with the eight animals used in 

 these tests are summarized. 



By referring to this table it will be seen that when the anterior 

 surface of only one eye is illuminated Vanessa usually turns 

 toward the shaded eye when first exposed, but that later it turns 

 consistently toward the illuminated eye. Consequently, since 

 it always turns toward the illuminated eye when the posterior 

 surface is exposed, it is evident that the reactions may depend 

 to some extent upon localization of the photic stimulus in the 

 eye. 



The results presented in this section show, moreover, that the 

 tension of the muscles in the legs on either side is not specifically 

 dependent upon chemical changes in either eye, as demanded 

 by the 'continuous action theory,' for without any change in 

 the illumination of a given surface of one eye the animal may 

 turn either to the right or to the left. 



GENERAL SUMMARY AND CONCLUSIONS 



1. Vanessa antiopa creeps and flies toward a source of light, 

 that is, it is positive in its reactions to light, never negative. 



2. Butterflies of this species, in direct sunlight come to rest 

 with the head away from the source of light. 



3. When placed in a horizontal beam so as to face the light 

 Vanessa with one eye blackened usually turns toward the func- 

 tional eye. In some cases it continues to turn in this direction 

 and consequently performs circus movements both in the beam 

 and in the shaded region beyond it ; usually, however, it proceeds 

 in a fairly straight course diagonally across the beam until the 

 edge of the beam is reached, where it usually turns toward the 

 covered eye and moves directly toward the source of light. Some- 



