iv.] POWER OF APPRECIATING COLOUR. 131 



10 ... Violet. Green. Yellow. Red. 



11 . 



12 . , 



Adding these numbers together, there were, in the 

 twelve observations, under the red 890, under the green 

 544, under the yellow 495, and under the violet only 5. 

 The difference between the red and the green is very 

 striking, and would doubtless have been more so, but for 

 the fact, that when the colours were transposed, the ants 

 which had collected under the red sometimes remained 

 quiet, as, for instance, in cases 7 and 8. 



The case of the violet glass is more marked and more 

 interesting. To our eyes, the violet was 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. 



Lasius flavus also showed a marked avoidance of the 

 violet glass. 



I then experimented in the same way with a nest of 

 Formica fusca, in which there were some pupse, which 

 were generally collected in a single heap. I used glasses 

 coloured dark yellow, dark green, light yellow, light 

 green, red, violet, and dark purple. The colours were 

 always in the preceding order, but, as before, their place 

 over the nest was changed after every observation. 



To our eyes, the purple was almost black, the violet 

 and dark green very dark and quite opaque ; the pupse 



K 2 



