OCCASIONAL NOTES. 341 
some Ants with larve and pup between two plates of glass about one- 
eighth of an inch apart, a distance which leaves just room enough for the 
Ants to move about freely. He found that if he covered over part of the 
glass with any opaque substance the young were always carried into the 
part thus darkened. He then tried placing over the nest different coloured 
glasses, and found that if he placed side by side a pale yellow glass and one 
of deep violet, the young were always carried under the former, showing 
that though the light yellow was much more transparent to our eyes it was, 
on the contrary, much less so to the Ants. So far he had gone in experi- 
ments already recorded. But he now wished, as already mentioned, to go 
further, and test the effect upon them of the ultra violet rays, which to us 
are invisible. For this purpose, among other experimeuts, he used sulphate 
of quinine and bisulphide of carbon, both of which transmit all the visible 
rays, and are therefore perfectly colourless and transparent to us, but 
which completely stop the ultra violet rays. Over a part of his nest he 
placed flat-sided bottles containing the above-mentioned fluids, and over 
another part a piece of dark violet glass; in every case the larve were 
carried under the transparent liquids and not under the violet glass. Again, 
he threw a spectrum into a similar nest, and found that if the Ants had to 
choose between placing their young in the ultra violet rays or in the red, 
they preferred the latter. He infers therefore that the Ants perceive the 
ultra violet rays which to our eyes are quite invisible. Now, as every ray 
of homogeneous light which we can perceive at all appears to us a distinct 
colour, it seems probable that these ultra violet rays must make themselves 
apparent to the Ants as a distinct and separate colour (of which we can 
form no idea), but as unlike the rest as red is from yellow or green from 
violet. The question also arises whether white light to these insects would 
differ from our white light in containing this additional colour. At any 
rate, as few of the colours in nature are pure colours, but almost all arise 
from the combination of rays of different wave-lengths, and as in such cases 
the visible resultant would be composed not only of the rays which we see, 
but of these and the ultra violet, it would appear that the colours of objects 
and the general aspect of nature must present to them a very different 
appearance from what it does to us. Similar experiments which Sir John 
also made with some of the lower Crustacea points to the same conclusion, 
but the account of these he reserved to a future occasion. He then 
proceeded to describe some experiments made on the sense of direction 
possessed by Ants, but it would not be easy to make these intelligible 
without figures. After detailing some further experiments on the power of 
recognising friends, he gave some facts which appear to show that Ants by 
selection of food can produce either a queen ora worker at will from a 
given egg. Lastly, he stated that he had still some Ants which he had 
commenced to observe in 1874, and which are still living and in perfect 
