EEACTIONS TO LIGHT IN VANESSA ANTIOPA 369 



the behavior in hght was made in a dark room under accurately 

 controlled environmental conditions. In these experiments the 

 animals were exposed in a horizontal beam produced by means 

 of a 110 volt Nernst glower. The glower was mounted in front 

 of a small opening in a light-proof box that was painted dead 

 black inside, so as to form a non-reflecting background. It was 

 placed 10 cm. from and at the same level with the top of a table 

 on which the animals were tested. By means of screens the 

 light from the glower was so cut down as to produce a sharply 

 defined beam of the size desired. The edges of this beam could 

 be clearly seen on the black top of the table. This beam was 

 the only light in the room, and this was in large part absorbed 

 by means of dull black paper hung over the exposed walls. 

 There was consequently very little light in the room aside from 

 that in the beam. Under these conditions therefore, the animals 

 were exposed in a beam of light from a single, small and con- 

 centrated source. 



The limits of this beam were very apparent in the dark room 

 in which the experiments were made. The nature of the source 

 of light and the sharply defined character of the beam are im- 

 portant, for experiments described later demonstrate that the 

 behavior of animals with one eye blackened depends to a marked 

 extent upon whether there are one or more sources of light 

 present. 



Not only was the behavior of the animals described by the 

 observer, but the butterflies, themselves, were forced to make 

 permanent records of their own behavior. This was done by 

 allowing them to walk on sheets of paper which had been covered 

 with soot from an oil lamp. These sheets measured 20 x 25 cm., 

 but in some experiments, a number of them were placed side by 

 side until the area was as large as desired. The tracings made 

 by the insects were made permanent by means of a coat of 

 shellac. The buttprflips wprp freauently allowed to walk over 

 the sheets of paper covered with soot, and then the same experi- 

 ment was repeated without the use of the blackened paper. 

 The same results were secured in both cases. This shows that 

 the behavior was not affected by the soot. This method of hav- 



