RELATED STUDIES AND CRITIQUES. 183 



place and not finding the flowers precipitated themselves upon the imita- 

 tion, as upon any object whatsoever. The same objection was raised to 

 the experiments with the poppy, the results of which were regarded as 

 illusory because of this fact, as well as because the flowers were cut off and 

 handled, and to those with Dahlia. The experiments with Zinnia were 

 also regarded as demonstrating nothing whatsoever, since the artificial 

 flowers were attached to the stems to which the bees were accustomed to 

 come to visit the natural ones. Moreover, it was supposed that the meshes 

 of the wire-gauze were so small that the odor could escape little if at all. 

 Both of these objections were also urged against the results obtained with 

 Salvia horminum, but their validity does not seem to be great, and they 

 can not apply to the many cases in which the artificial flowers were placed 

 at distances of several meters. 



Wery's experiments with decorollate and artificial flowers. — At 



the suggestion of Errera and Massart, and under their supervision, Wery 

 (1904:1211) made a series of investigations to determine whether color 

 exerted an attraction upon insects and whether this was greater or less than 

 that due to odor. An interesting historical introduction is given, but no 

 direct criticism of Plateau's work is made, except to point out that this 

 investigator modified his earlier conclusions as to odor and color in 1899, 

 and in 1902 he admitted that he had ascribed an exaggerated importance 

 to odor. The first experiments with decorollate flowers demonstrated that 

 different insects behaved differently in response to color and odor, the higher 

 bees, Apis and Bombus, visiting the normal flowers in much greater number, 

 Eristalis showing a marked but slighter preference, and the flies and other 

 small Diptera exhibiting little difference. This showed that it was not 

 permissible to group such various insects together in studies of attraction 

 and consequently the visits of honey-bees alone were taken into account 

 in these experiments, a fact that explained in part their disagreement with 

 those of Plateau. A further explanation of this difference was afforded 

 by the fact that the bouquets were always separated by a distance of several 

 meters and sufficiently isolated to avoid errors due to any other attractive 

 object. Moreover, the flowers were changed about in order to eliminate 

 errors arising from the habits of the bees. The experimental area was stripped 

 of all other flowers and the space between these and the hive was cleared 

 of all plants, so that the bees flew straight from the hive in direct response 

 to attraction and the visits were not the result of hazard. The bouquets 

 were not exposed between experiments and the artificial flowers were put 

 away to make sure that the bees would not ignore them in consequence 

 of vain visits. An endeavor was made to count only the visits of bees coming 

 from the hive or from a distant flight during which they had gone to other 

 flowers. In removing the corolla care was taken not to injure the nectaries 

 and great care was also given to following the precautions laid down by 

 Plateau, such as washing the hands, avoiding the use of perfume, not touch- 

 ing the flowers with the hands and using the scissors for no other purpose. 

 The objection of Plateau that insects would not visit cut flowers was not 

 confirmed, except when the temperature was unfavorable, as at other times 

 they were abundantly visited by insects of diverse species. 



