206 THE EVOLUTION THEORY 



bees than of the greater visibility of the colour in question in the 

 environment peculiar to the flower, and of the amount of rivalry 

 the bees meet with from other insects in regard to the same flower. In 

 individual cases this would be difficult to demonstrate, especially since 

 we can form only an approximate idea of the insect's power of seeing 

 colour, and cannot judge what the colours of the individual blossoms 

 count for in the mosiac picture of a flowery meadow. Yet this is the 

 important point, for, as soon as the bees perceive one colour more 

 readily than another, the preponderance of this colour-variety over 

 other variations is assured, since it will be more frequently visited. 

 In the same way we cannot guess in individual cases why one species 

 of flower should exhale perfume while a nearly related species does 

 not. But when we remember that many flowers adapted for the 

 visits of dipterous insects possess a nauseous carrion-like smell, by 

 means of which they not only attract flies but scare off other 

 insects, we can readily imagine cases in which it was of importance 

 to a flower to be able to be easily found by bees without 

 betraying itself by its pleasant fragrance to other less desirable 

 visitors. 



Thus, therefore, we can understand the odourless but intensely 

 blue species of gentian, if we may assume that its blue colour is more 

 visible to bees than to other insects. If I were to elaborate in detail 

 all the principles which here suggest themselves to me I should 

 require to write a complete section, and I am unwilling to do this 

 until I can bring forward a much larger number of new observa- 

 tions than I am at present in a position to do. All I wish to do 

 here is to exhort doubters to modesty, and to remind them that these 

 matters are exceedingly complex, and that we should be glad and 

 grateful that expert observers like Darwin and Hermann Muller have 

 given us some insight into the principles interconnecting the facts, 

 instead of imagining whenever we meet with some little apparently 

 contradictory fact, which may indeed be quite correct in itself, 

 that the whole theory of the development of flowers through 

 insects has been overthrown. Let us rather endeavour to under- 

 stand such facts, and to arrange them in their places as stones of 

 the new building. 



Often the contradiction is merely the result of the imperfect 

 theoretical conceptions of its discoverer, as we have already shoAvn in 

 regard to Nageli. Bulman, too, fancies he has proved that bees do 

 not distinguish between the different varieties of a flower, but visit 

 them indiscriminately with the same eagerness, thus causing inter- 

 crossing of all the varieties, and preventing any one from becoming 



