RATE OF LOCOMOTION IN VANESSA ANTIOPA 



513 



by a small motor was placed vertically at one end of the table 

 described above. The motor rested upon a thick pad of woolen 

 cloth to prevent vibration as far as possible. Sectors of various 

 sizes were cut out of the disc. A 36 c.p. automobile lamp was 

 used as a source of light. It was placed in a black box in one 

 end of which was an adjustable slit. This source of light was 

 placed behind the disc. From the lamp emanated a horizontal 

 beam which extended the length of the table. By means of a 

 rheostat inserted in the circuit the rapidity of the rotation of the 

 disc could be regulated, and so intermittent light of the frequency 

 of interruption desired could be secured. By moving the disc 

 to one side a beam of continuous light was obtained. The table 

 was marked off into sections as in the previous experiment. The 

 rate of movement of the insects was measured as before. Three 

 different experiments were performed which may be designated 

 as experiments 3, 4, and 5. 



TABLE 4 



Rate of locomotion of Vanessa antiopa in intermittent light of a frequency of inter- 

 ruption of 10 per second, the periods of illumination and non-illumination being 



equal 



