ui] THE FERTILISATION OF FLOWERS. 39 
sively. Hesays: “That bees are attracted by, and 
can distinguish, colours was no doubt a just inference 
from the observations on their relations to flowers; 
but I am not cognisant of any direct evidence on the 
subject. I thought it, therefore, worth while to make 
some experiments; and a selection from them will 
be recorded in the forthcoming volume of ‘Journal 
of the Linnean Society.’ I placed slips of glass 
with honey on paper of various colours, accustoming 
different bees to visit special colours, and when they 
had made a few visits to honey on paper of a par- 
ticular colour, I found that if the papers were trans- 
posed the bees followed the colours.” * 
If bees in a garden are watched, they will be seen 
to confine their attention to one particular species, 
though they have been observed to be incapable of 
distinguishing between certain closely-related species, 
though this may indicate that they are not true species, 
but only varieties, 
Most flowers which have an zrregular corolla—that 
is, with the petals unequal in size and form—are, 
according to Mr. Darwin, insect-fertilised; and he 
says it is very probable that those species which are 
habitually self-fertilised receive fresh vigour from an 
occasional cross. Sir John Lubbock, in his charming 
book, has entered fully into the question as affecting 
our native wild plants, and has given examples from 
most of the natural orders and families, It is impos- 
sible in the small space at present at our disposal to 
do more than give a few of the most striking illustra- 
tions. Why should the bees and other insects go to 
* Wild Flowers in Relation to Insects, p, 12 
