124 SIE JOHN LUBBOCK ON AXTS, BEES, AND WASPS. 
esculine, which is impervious to the ultra-violet rays, and a glass 
of deep cobalt, which stopped most of the other rays hut 
permitted the ultra-violet to pass. The results then were : — 
Under the Esculine. 
Under the Cobalt 
glass. 
Hoodwinked Ants. 
Normal Ants. 
Hoodwinked Ants. Normal Ants. 
11 
8 
3 
1 
11 
13 
4 
2 
9 
12 
5 
3 
5 
13 
9 
2 
10 
12 
4 
3 
3 
11 
12 
3 
12 
13 
3 
1 
61 
82 
40 
15 
Thus, then, a very large proportion of the normal ants preferred 
to avoid the ultra-violet rays by going under the esculine. To 
the varnished ants, on the contrary, it was indifferent whether 
they were under the esculine or the cobalt. The slight prepond- 
erance in favour of the esculine vas probably partly due to having 
started the experiments with a larger number of auts in the side 
of the box then covered with esculine, and partly from the fact 
that the hoodwinked ants would have a tendency to accompany 
the others. 
Erom these and other experiments M. Eorel comes to the same 
conclusion as I did, that the ants perceive the ultra-violet rays 
with their eyes ; and not, as suggested by Graber, by the skin 
generally. 
Experiments with Platyarthrus. 
In connection with this subject I may add that I do not at all 
doubt the sensitiveness to light of eyeless animals. In experi- 
menting on this subject I have always found that though the 
Platyarthrus , which live with the ants, have no eyes, yet if part 
of the nest be uncovered and part kept dark, they soon fiud 
their way into the shaded part. It is, however, easy to imagine 
that in unpigmented animals, whose skins are more or less semi- 
transparent, the light might act directly on the nervous system, 
even though it could not produce anything which could be called 
vision. 
