208 EXPERIMENTS WITH HOODWINKED ANTS. 



Forel, in some recent experiments, varnished over 

 the eyes of fifteen ants (Camponotus Ugniperdus) and 

 put them with fifteen others, wliich were left in their 

 normal condition, in a flat box with a glass top and 

 divided in the middle into two halves by a cardboard 

 division, which, however, left room enough underneath 

 for the ants to pass freely from one half to the other. 

 After some other experiments, in the course of which 

 one of the varnislfed ants was accidentally killed, at 

 1 p.m. all the varnished ants and thirteen of the un- 

 varnished were in the right half of the box, and two 

 unvarnished in the left. He then placed over the 

 whole box two flat bottles containing water to inter- 

 cept heat- rays — over the right half a piece of cobalt 

 (violet) glass ; and over the left, a flat bottle containing 

 a solution of esculine, which is quite transparent, but 

 cuts off the ultra-violet rays. At 1.55 the result was 

 as follows : — 



Under the esculine. Under the cobalt. 



5 varnished. 9 varnished. 



13 normal. 2 normal. 



The esculine and cobalt were then transposed. At 

 2.3 the position was — 



Under the cobalt. Under the esculine. 



4 varnished. 13 varnished. 



3 normal. 12 normal. 



The esculine and cobalt were again transposed, and 

 one normal ant was accidentally wounded and removed. 

 At 3.8— 



Under the esculine Under the cobalt. 



3 varnished. 12 varnished. 



11 normal. 3 normal. 



