202 EXPERIMENTS WITH ELECTRIC LIGHT. 



rays were moved first, and were deposited, the larvae in 

 the violet, and the pupae in the red. 



Experiment 4.— Made the same experiment with 

 another nest of L. niger. At the commencement the 

 larvae and pupae were in the violet and ultra-violet 

 portion, extending to double the distance from the 

 visible end to the thalline band. The ants soon began 

 bringing the pupae to the red. Over part of the red I 

 placed a piece of money. The pupse were cleared from 

 the ultra-violet first. That the pupae were not put in 

 the red for the sake of the red light was evident, 

 because the space under the coin was even more 

 crowded than the rest. The pupae were heaped up in 

 the dark as far as the thalline band of the other spec- 

 trum. I then brought the second spectrum nearer to 

 the first. The pupae which thus came to be in the 

 thalline band were gradually moved into the dark. 



Experiment 5. — Tried the same with another nest 

 of L. niger. The pupae were at first in the \iolet and 

 ultra-violet about double as far as the thalline line, 

 while most of the larvae were in the green. The 

 furthest part was cleared first ; and they were again 

 brought principally into the yellow, red, and dark. 



Again, I scattered them pretty equally, some being 

 in the ultra-violet portion, as far as double the distance 

 of the thalline from the vdolet ; most, however, being 

 in the violet and blue. 



The ants began by removing the pupae which were 



