12 BEES AND COLOU'RS. [chap. 



on the stamens, according to MuUer, in Pulsatilla ; 

 and on the ovary, in Caltha. 



The pollen, of course, though very useful to insects, 

 is also essential to the flower itself ; but the scent and 

 the honey, at least in their present development, are 

 mainly useful in securing the visits of insects, though 

 the honey is also sometimes of service in causing the 

 pollen to adhere to the proboscis of the insect. 



That bees are attracted by, and can distinguish, 

 colours, was no doubt a just inference from the 

 observations on their relation to flower?, 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 the 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- 

 Vticular colour, I found that if the papers were trans- 

 posed the bees follov/ed the colour. 



But if flowers have been modified with reference 

 to the visits of insects, insects also have in some cases 

 been gradually modified, so as' to profit by their visits 

 to flowers. This is specially the case with reference 

 to two groups of insects, namely. Bees and Butter- 

 flies, which have been specially studied by H. Miiller 

 with reference to this point ; and from his works 

 the following facts are mainly taken. Although the 

 whole organisation of the insect might be said to 

 have reference to these relations, still the parts which 

 iiave been the most profoundly altered are the mouth 



