<54b TEE AMEBIC AN NATURALIST [Vol. XLIII 



they succeeded in finding the central florets beneath the 

 leaves ; but to the dahlia with the disc exposed and the 

 rays covered they continued to fly as usual. But the bees 

 remembered the earlier condition of the dahlia bed and 

 seemed to be seeking the dahlia heads which had so sud- 

 denly disappeared. Soon a poorly concealed specimen 

 was detected and visited, then another, and at the end 

 of about three hours the entrances at the side and below 

 were discovered and the hidden flowers were again being 

 visited. Forel says : 



" Plateau, therefore, conducted his experiments in a faulty manner 

 and obtained erroneous results. The bees still saw the Dahlias which 

 he at first incompletely concealed. Then, by the time he had covered 

 them up completely, but only from above, they had already detected 

 the fraud and saw the Dahlias also from the side. Plateau had failed 

 to take into consideration the bees' memory and attention." 



To Forel 's criticisms published, in 1901, in Rivista di 

 Biologia Generate, Plateau has replied in part: That not 

 only bees but numerous diurnal lepidoptera visited the 

 masqued dahlias, and that while it was freely admitted 

 that insects could see the under side of the covered 

 capitula and the radiating form and red or rose color 

 of the floral ligules, yet they were without attractive 

 value, as it was only very rarely that an insect ap- 

 proached the inflorescence of this side. 7 To these state- 

 ments I will again refer later. His further explanations 

 as well as his assertions that his opinions have in some 

 particulars been misunderstood by Forel are immaterial 

 to the present discussion. But in admitting that the 

 visits of hymenoptera can be partially explained by 

 memory Plateau practically abandons his position so far 

 as his experiments with dahlias are concerned. 



Forel, as has already been mentioned, points out that 

 Plateau has attached too little importance to the bee's 

 memory and attention. These are, indeed, qualities more 

 likely to be appreciated by the practical apiarist than the 



