280 SIE JOHN LUBBOCK; OK ANTS, BEES, AND WASPS. 



ence between the yellow and green, we must remember also that 

 the green was decidedly more opake than the yellow. 



The case of the violet glass is more marked and more interesting. 

 To our eyes the violet was as opake 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. 



iMsiusJlavus'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 pupae, which were generally col- 

 lected 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 opake ; the pupae could be dimly 

 seen through the red, rather more clearly through the dark yellow 

 and light green, while the light yellow were almost transparent. 

 There were about 50 pupae, and the light was the ordinary diifused 

 daylight of summer. (See Table, p. 281.) 



These observations show a marked preference for the greens 

 and yellows. The pupae were 6|- times under dark green, 3 under 

 dark yellow, 3^ under red, and once each under light yellow and 

 light green, the violet and purple being altogether neglected. 



I now tried the same ants under the same colours, only in the 

 sun ; and placed a shallow dish containing some 10 per cent, so- 

 lution of alum sometimes over the yellow, sometimes over the red. 

 I also put four thicknesses of violet glass, so that it looked almost 

 black. (See Table, p. 282.) 



Under these circumstances, the pupae were placed under the red 

 7i times, dark yellow 5|-, and never under the violet, purple, light 

 yellow, dark or light green. 



The following day I placed over the same nest, in the sun, dark 

 green glass, dark red and dark yellow (two layers of each). In 

 nine observations the pupae were carried 3 times under the red 

 and nine times under the yellow. 



I then tried a similar series of experiments with Lasius 

 niger, using part of a nest in which were about 40 pupae, 

 which were generally collected in a single heap all together. 

 As before, the glasses were moved in regular order after each 



