RATE OF LOCOMOTION IN VANESSA ANTIOPA 



509 



cession in artificial light. In the case of 7 of the animals the 

 tests in sunlight preceded those in weak light, while in the case 

 of the remaining 7 animals the reverse was true. The beam of 

 sunlight throughout the whole length of the table was approxi- 

 mately 5000 m.c. The beam of artificial light was 10.07 m.c. 

 at one end of the table and 0.01 m.c. at the other. In table 1 

 are presented the results obtained. These results show that 

 10, or over 71 per cent of the insects moved faster in the weaker 

 light, and that only 4, or nearly 29 per cent, moved faster in 

 the stronger light. It shows also that the average rate of move- 

 ment per second of all 14 butterflies in direct sunlight was 

 only 2.831 cm., while in weak light it was 3.334 cm. This in- 

 dicates that Vanessa antiopa usually moves faster in weak light 

 than in strong light, if the difference in illumination is great. 



TABLE 1 



Rate of locomotion of Vanessa antiopa in two luminous intensities, one from nearly 

 500,000 to nearly 500 times the other at the two ends of a 300 cm. course 



