32 ANIMAL INTELLIGENCE. 



following results. The ants which he observed greatly 

 dislike the presence of light within their nests, hurrying 

 about in search of the darkest corners when light is ad- 

 mitted. The experiments showed that the dislike is much 

 gr 3ater in the case of some colours than in that of others. 

 Thus under a slip of red glass there were congregated on 

 one occasion 890 ants, under green 544, under yellow 495, 

 and under violet only 5. To our eyes the violet is as opaque 

 as the red, more so than the green, and much more so 

 than the yellow. Yet, as the numbers show, the ants had 

 scarcely any tendency to congregate under it : there were 

 nearly as many under the same area of the uncovered 

 portion of the nest as under that shaded by the violet 

 glass. It is curious that the coloured glasses appear to act 

 on the ants in a graduated series, which corresponds with 

 the order of their influence on a photographic plate. Ex- 

 periments were therefore made to test whether it might 

 not be the actinic rays that were so particularly distasteful 

 to the ants ; but with negative results. Placing violet 

 glass above red produces the same effect as red glass 

 alone. Obviously, therefore, the ants avoid the violet 

 glass because they dislike the rays which it transmits, 

 and do not prefer the other colours because they like the 

 rays which they transmit. Sodium, barium, strontium, 

 and lithium flames were also tried, but not with so much 

 effect as the coloured glass. 



It has just been observed that the relative dislike which 

 Sir John Lubbock's ants showed to lights of different colours 

 seems to be determined by the position of the colour in 

 the spectrum there being a regular gradation of intole- 

 rance shown from the red to the violet end. As these ants 

 dislike light, the question suggests itself that the reason 

 of their graduated intolerance to light of different colours 

 may be due to their eyes not being so much affected by 

 the rays of low as by those of high refrangibility. In this 

 connection it would be interesting to ascertain whether 

 ants of the genus Atta show a similarly graduated intole- 

 rance to the light in different parts of the spectrum ; for 

 both Moggridge and MacCook record of this genus that it 

 not only does not shun the light, but seeks it coming to 



