392 



WILLIAM L. DOLLEY, JR. 



The organism is non-symmetrical, only one eye being functional. 

 And yet the butterfly moves toward a source of light, deflecting, 

 it is true, toward the functional eye, and when the position of 

 the light is changed, the animal also changes the direction of its 

 motion to correspond with the change in position of the source 

 of light. This behavior bears little resemblance to that which 

 would be (exhibited were the organism such that it could only 



Fig. 11 Reproduction of trails made by four butterflies showing reorientation. 

 Large arrows, A and B, direction of rays of liglijt in the two positions of the 

 glower; small arrows, direction of movement of the butterflies; x, position of 

 animals when the direction of the rays was changed ; 1 and 2, trails made by butter- 

 fly 7/29-d; (left eye blackened) ; 3 and 4, trails made by butterfly 7/16-c (left eye 

 blackened) ; 5 and 6, trails made by butterfly 7/29-b (left eye blackened) ; 7 and 

 8, trails made by butterfly 9/22-b (right eye blackened). 



