210 PRINCIPLES AND CONCLUSIONS. 



insects direct themselves toward flowers which provide them with the nourishment 

 that they need, and that they find them as well when they are as green as the leaves, 

 as when they are blue, red, or yellow. Inversely, they ignore the most beautiful 

 flowers with striking colors, when these have nothing to give them. Plateau gives 

 himself unnecessary trouble to show that there are green flowers and that insects 

 visit them as much as others. Every one knows the first of these facts, and the second 

 has escaped no entomologist; in my opinion, his long comparative tables refute Mueller. 

 Nevertheless, do there exist any preferences of color beside the fundamental fact 

 that we have enunciated? This is so difficult and so delicate to decide that I dare not 

 express an opinion. 



"But Plateau has completed his old experiments on another very interesting point. 

 I refer to artificial flowers. He has taken enormous trouble to obtain the best and most 

 artistic imitations of natural flowers. To one who knows modern art in this branch 

 this means much, for even man needs all his attention to enable him to distinguish 

 these artificial products from true flowers. Here again I am pleased to be able to 

 confirm Plateau by several experiments that I have been able to make. That which 

 deceives us never deceives insects, or hardly ever, and then only for an instant. The 

 insect passes to one side of artificial flowers without paying them attention, without 

 stopping at them, without hesitating, and goes straight to natural flowers situated 

 beside them, and which we do not distinguish from them. Ought we to conclude 

 therefrom that the colors which we use, and which are not chlorophyllic, are dis- 

 tinguished by insects from chlorophyllic colors? This appears very probable from 

 Plateau's experiments, and I shall believe it until I have proof to the contrary. That 

 which to our eyes is a good imitation of color appears not to be so to the insect eye. 

 These facts will appear less astonishing to us if we remember that among men some 

 are color-blind, while others are artists who render and appreciate colors in many 

 various shades. Then we must not forget that artificial imitations of flowers are made 

 by the help of human vision and for it. 



"I shall not enlarge upon the researches of Mueller, Bennett, Bonnier, Gratacap, 

 Christy, Bulman, Scott Elliot, Delpino, Kuntze, Knuth, and Plateau on the truly hair- 

 splitting question regarding the possibility of insects having preferences for certain 

 colors or not. Here I am in agreement, as I have said, with Plateau (and Bulman). 

 What is astonishing is that so many authors can waste so much ink in proof of the 

 obvious, clearly summed up by Bulman when he saj^s, '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.' Only the fact that any color does not attract specially by itself 

 some insect is no proof that the latter cannot distinguish other colors. 



"But here my agreement with Plateau ceases. Here again he has drawn erroneous 

 conclusions from his experiments. In the case of masked dahlias, he concludes that 

 shape and color do not attract, but forgets that the insect remembers the place where 

 the flower was. Plateau's observations and inferences are both faulty. First, his 

 dahlias were insufficiently masked, being covered only in the upper part; bees flying 

 around a group of flowers must perceive the uncovered colored sides by their 

 peripheral vision. This seems to be evident from the figures of Plateau, which 

 shows the vine leaf lying flat on the flower. In the second place his bees had conse- 

 quently discovered his trick sooner than mine; he probably took no account of their 

 behavior at the beginning of his experiment, or had not noted it. But it is only at 

 such a time that conclusions can be drawn as to vision alone, independently of 

 memory. Further, our results show that bees have a poor sense of smell at a distance. 



"Plateau also worked with bees that were visiting Oenothera biennis with its beautiful 

 yellow petals. On September 3rd he cut the corollas, leaving only the stamens. 

 I give the results in his own words: — 'The bees visiting the plant flew in every direction, 

 toward the faded flowers, towards the buds, even to the fallen petals on the ground, 

 which they examined with some attention in walking over them; nevertheless, 



