402 



WILLIAM L. DOLLEY, JR. 



this tendency is in general retained for several successive days, 

 although some modification in reactions is evident. This state- 

 ment, that there is some change in behavior, is supported by the 

 fact that of the nine animals tested on more than one day five 

 continued to perform circus movements on the first day of the 

 tests, but on succeeding days in some trials went in courses which 

 were more or less straight for several centimeters. 



Fig. 17 Reproduction of trails made in trials on three successive days in non- 

 directive light of 6 inc. by butterfly 7/11-3 (right eye blackened) . a, trails made 

 in three trials on the first day, b, trails made in eight trials on the second day, 

 c, trails made in six trials on the third day. Note that the insect moved in 

 rather straight courses on the second day, while on the first and third days it 

 usually turned continuously toward the functional eye. 



From time to time throughout the entire period, the animals 

 used in the experiment above were tested in a horizontal beam. 

 In the beginning some of them made circus movements, and 

 some did not, but at the close of the experiment none of them 

 made circus movements. This is of great interest, for in non- 

 directivQ light these insects continued to make circus movements 

 throughout the entire period. Under both conditions, only one 



