FIG. 2. Paths of a typical specimen of Vanessa in a field of light composed of 

 two horizontal beams of equal illumination crossing at right angles, the light in 

 one beam being continuous and that in the other intermittent. (Reduced by 

 three-fourths). The intermittent light was produced by a rotating sectored disk 

 with one-fourth removed. Arrows to the left, direction of the rays of intermittent 

 light; arrows below, direction of the rays of continuous light. Flash-frequency 

 of intermittent light in A, 30; in B, 20; in C, 10; in D, 5; in E, 2 per second. 

 Illumination in each beam, 3.5 m.c. Figures above and to right, degree of 

 deflection in individual trials from line bisecting angle between the two beams. 

 "Plus" indicates deflection toward source of intermittent light; "minus," toward 

 source of continuous light. Figures in upper left hand corners indicate the av- 

 erage angle made in each group of 10 trials. The angles given in table 5 for this 

 butterfly (25) are the average of 20 trials. In this figure only 10 of them under the 

 different conditions are presented. Note that the degree of deflection varied 

 with the flash-frequency. When the frequency of interruption was 2 per second 

 the butterfly moved toward a point near the source of continuous light. When 

 the frequency of interruption was 20 and 30 per second the organism moved toward 

 a point some distance from the source of intermittent light. At intermediate 

 flash-frequencies it moved toward points between the above. 



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