24 ANTS AND SOME OTHER INSECTS. 



facts in almost as great numbers as to the Dahlias, but at once 

 abandoned the flowers when they had detected the error, obviously 

 by means of their sense of smell. The same results were produced 

 by a Dahlia, the disc of which had been replaced by the disc of a 

 Hieracium. 



As a control experiment I had placed a beautiful, odorous 

 Dahlia disc among the white and yellow Chrysanthemums which 

 had been neglected by the bees. For a whole half hour the bees 

 flew by only a few centimeters above the disc without noticing it ; 

 not till then was it visited by a bee that happened to be followed 

 by a second. From this moment the Dahlia disc which lay in the 

 path of flight was visited like the others, whereas on the other hand 

 the Petunia-Hieracium artefacts, now known to be fraudulent, were 

 no longer noticed. 



Plateau has demonstrated that artificial flowers, no matter how 

 carefully copied from the human standpoint, are not noticed by in- 

 sects. I placed artefacts of this description among the Dahlias. 

 They remained in fact entirely neglected. Perhaps, as above sug- 

 gested, the bees are able to distinguish the chlorophyll colors from 

 other artificial hues, owing to admixtures of the ultra-violet rays, 

 or by some other means. But since Plateau imagines that the arti- 

 ficial flowers repel insects, I cut out, Sept. igth, the following 

 rather crude paper-flowers : 



a. A red flower ; 



ft. A white flower ; 



y. A blue flower ; 



8 A blue flower, with a yellow center made from a dead leaf; 



e. A rose-colored piece of paper with a dry Dahlia disc; 



. A green Dahlia leaf (unchanged). 



It was nine o'clock in the morning. I placed a drop of honey 

 on each of the six artefacts mounted among the Dahlias. For a 

 quarter of an hour many bees flew past, very close to my artefacts 

 but without perceiving and hence without smelling the honey. I 

 went away for an hour. On my return artefact 8 was without honey, 

 and must therefore have been discovered by the bees. All the 

 others had remained quite untouched and unnoticed. 



