feb. 1899] BEES AND THE ORIGIN OF FLOWERS T29 



species it cannot raise one or more of these to the rank of distinct 

 species at the expense of the others, as it ought to do on the principles 

 of natural selection. Again, admitting that all species, sub-species, 

 and varieties as they exist to-day are sterile inter sc, we cannot 

 suppose that the varying individuals in a species — which must form 

 the beginning of a new species — are so. And it is with such that the 

 bee has to deal at the beginning of the development. Ce nest que le 

 premier pas qui coute. but if you cannot take the first step it does not 

 matter how easy the rest are. Thus the principle of physiological 

 selection will scarcely man the breach caused by the loss of the con- 

 stancy of the bee. But can we accept fully the principle that 

 varieties are as a rule sterile inter se ? Dr. Romanes, indeed, seems 

 to have accepted it unreservedly, but it is hard to resist the conviction 

 that had it been less in accordance with his theory of physiological 

 selection he would have subjected the evidence to more rigid criticism. 

 The experiments, we may note, were made some twenty-five years 

 ago, and do not appear to have been since confirmed. They were 

 also avowedly made for the purpose of proving that each species 

 and variety had been specially created. Darwin, moreover, found that 

 crosses between slight varieties were more, and not less, fertile than 

 those between individuals of the same variety. This is also the 

 experience of gardeners and breeders. 



With regard to the question of the influence of colour on insects, 

 Mr. Headley writes as follows : — 



" To account, then, for the colours of flowers we have the proved 

 colour-sense of bees. Sir John Lubbock has tested it by experiment : 

 they are attracted by brilliant blossoms, and, therefore, it has been to 

 the interest of plants, in order to obtain cross-fertilisation, to produce 

 conspicuous flowers." 



But whoever ventures to form an opinion on this very difficult 

 subject will have also to take account of the exhaustive experiments 

 recently carried out by Professor Plateau of Ghent. That gentleman 

 concludes, as the result of his researches, that insects are attracted 

 to flowers in a very subordinate way by sight, and chiefly by another 

 sense, viz. smell. My own observations do not lead me to go so far 

 as to say that the colours of flowers have nothing to do with attracting 

 insects to them. But I do most emphatically assert that they are 

 indifferent as to what particular colour the flower they visit is. As 

 far as I am able to judge, it matters not one iota to a bee whether 

 the flower is blue, red, pink, yellow, white, or green : so long as there 

 is honey, that is sufficient. Indeed, we sometimes hear of bees gather- 

 ing the honey-dew from the leaves of trees, visiting sugar refineries, 

 and robbing jam factories. 



As regards the supposed constancy of bees in visiting flowers Mr. 

 Headley expresses his opinion thus : — 



" That they show a remarkable degree of constancy is undeniable. 



