178 PRINCIPLES AND CONCLUSIONS. 



ferent color were vitiated by the bees' power of memory, the marked bees 

 placed on the blue disks beginning at once to investigate all the other colors 

 with and without honey, and being followed by a swarm that even besieged 

 the paint-box. 



Response of Syritta. — Schroder (1901: 181) recorded 12 cases in which 

 a honey-bee approached to within 2 dm. of heads of Chrysanthemum leu- 

 canthemum and then flew to a bush of jasmine at a distance of 4 meters, 

 the strong fragrance of which was carried across the former. He clipped the 

 rays from half a group of 12 heads and found that Syritta pipiens in the 

 course of a half-hour visited 37 normal heads, while it completely ignored 

 the mutilated ones. Syritta hovered over the latter a longer time than usual, 

 but without alighting. During the afternoon, 4 visits were made to the 

 clipped heads and 21 to the normal, and on the next day 19 to 46, the fly 

 no longer showing the hesitation before the former. This indicated that the 

 insect recognized the difference in the heads in spite of the similar odor, and 

 that it learned rather rapidly to accustom itself to the mutilated ones. Two 

 days later the latter were cut off and a flat piece of white paper the size of 

 the head, provided in the middle with another piece the size and color of the 

 disk, was fastened on the end of the stem. In spite of visits to the normal 

 flowers, no Syritta paid the slightest attention to these crude imitations, 

 which lacked the form and fragrance of real flowers. They were then 

 furnished with a few drops of an infusion of Chrysanthemum heads, but, 

 while they were inspected during the next half-hour, no Syritta visited them. 

 However, when three of them were provided with honey, they received 10 

 visits during the half -hour to 12 for the normal ones. The other three were 

 also visited four times, indicating that Syritta had again profited by experi- 

 ence. Three artificial flowers made of cloth were fastened on the stem ends, 

 and one received a visit, but it was thought this might be due to the odor 

 of the adjacent normal heads. To give them a distinctive odor they were 

 soaked in the infusion of normal heads, dried, and again attached, when 

 they received 7 visits in comparison to 24 for the normal. Thus, the question 

 of the means by which flowers attract insects seemed not solved in the direc- 

 tion of Plateau's views. 



Andreae's experiments with artificial flowers.— In a comprehensive 

 examination of Plateau's results, Andreae carried out many experiments 

 with artificial flowers, some of these being made at Jena and some at Lake 

 Como (1903:427). In the first series yellow artificial flowers were placed 

 2 meters from a bed of Eranthis nivalis and these were visited during an 

 hour by 10 honey-bees. As a check a bell-glass was put over one plant to 

 eliminate the influence of odor, but in spite of this 4 honey-bees came to the 

 glass. When the imitations were replaced they were visited 8 times within 

 the hour. A further check was obtained by putting 10 decorollate flowers 

 in one beaker, 10 normal ones in a second, and the detached perianths in 

 a third. One honey-bee flew into the first glass and 2 hovered about it, 

 14 into the second and 10 about it, and 9 into the beaker with perianths 

 alone and 4 about it. When a dark paper was placed upon a small group 

 of Crocus and an artificial flower placed 2 meters away, bees went to the 

 latter, to Crocus, and again to the imitation before flying away to the snow- 



