168 PRINCIPLES AND CONCLUSIONS. 



but said nothing about the role of this when it was a question of flowers 

 already visited, or of faded flowers, buds, or fruits. The mistaken visits 

 to these were said to be directed by the form, poorly seen, the attraction 

 of which had been previously denied. In the case of withered flowers it 

 was thought clear that these were really visited because of the usual similarity 

 in color and not because of the form, as was likewise true in the case of many 

 buds. Imperfect vision of form can not serve to explain the majority of the 

 errors noted by Plateau, and form is to be regarded as the least important 

 of the features that effect attraction. 



Effect of colors at the hive. — Theen (1896:101) summarized the 

 results of a number of investigators on the color sense of bees, including the 

 little known ones of Wiist and of Donhoff. In Wust's apiary the thresholds 

 of the hives were painted with bright colors, which stood out sharply against 

 the deep-green of the Ampelopsis surrounding them on three sides. On one 

 occasion the supply of bright colors was inadequate and some thresholds 

 were painted black, red, or blue. The consequence was that the bees 

 required a longer time for recognition and were able to recognize the proper 

 hive at once only after the second day; at first it was necessary for them 

 to orient themselves for a much longer time in order to determine the right 

 hive. He also found that queen-bees were best equipped with the sense 

 of location and color. When a red petal of a poppy was placed on the yellow 

 threshold of a hive, a returning queen approached ten times as though to 

 enter and even alighted twice; it then quickly flew back, showing that she 

 recognized the place accurately, but found something there that was not 

 present when she flew out. Suddenly she flew away and was lost to view, 

 and the red petal was removed. After a few minutes she flew directly to 

 the threshold without hovering about and immediately disappeared. Don- 

 hoff pasted blue paper before a hive and 14 days later replaced it with a 

 yellow one. Bees returning from the field hesitated long before flying to the 

 hive and finally most of them flew to another part of the hive rather than 

 to the entrance. Theen also cited three observations of Darwin, in which 

 honey-bees flew directly from a tall larkspur in full bloom to one of another 

 species at a distance of 10 to 12 feet, though none of the flowers were open 

 and the buds showed but a tinge of blue. 



Critiques of Kienitz-Gerloff. — In a series of four reviews, Kienitz- 

 Gerloff considered the results and conclusions adduced in the five papers 

 of Plateau's first series. With reference to the response to masked Dahlia 

 heads he pointed out that the insects were readily guided by the sense of 

 smell, and that this did not warrant the assumption that the color of the 

 normal heads played no part in attraction, especially since no comparative 

 number of visits was given for the two kinds of heads. He cited the many 

 and varied experiments of Lubbock and of Mueller, and in particular those 

 of Forel with insects deprived of their antennae to show that the experiments 

 with Dahlia were not to be regarded as adequate. In opposition to the 

 conclusion of Graber that weakly refrangible light gives leucophobe animals 

 the impression of darkness, he brought forward the fact that all nocturnal 

 winged animals fly to lighted windows, indicating that they are drawn by 

 the contrast (1896: 123). In discussing the experiments in which the corolla 



