No. 510] COLOR SENSE OF THE HONEY-BEE 



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que Ton n'a certainement pas oublies et dan lesquelles je constatais de 

 multiples visites d'Insects a des fleurs dont toutes les parties colorees 

 etaient cachees par du feuillage. L'objection que les resultats de ces 

 experiences ancienne etaient precisement et exclusivenient dus au 

 souvenir de l'emplaceinent se presente immediatement a l'esprit." 



" Je reconnais bien volontiers que cette objection frappe juste pour 

 certaines des experiences en question." 5 



But in my experiments with the heads of simple dahlias 

 masqued with grape-leaves, Plateau continues, the mem- 

 ory of a place visited habitually does not wholly explain 

 the behavior of the insect visitors. In some instances 

 he covered up only the disc florets, leaving the ray florets 

 exposed ; in others he covered the entire upper face of the 

 capitulum, both ray and disc florets, but not the under 

 side, with green leaves, and both bees and butterflies 

 (species of Bombus, Megachile, Pieris and Vanessa) con- 

 tinued to fly toward the inflorescences and often found 

 the pollen and nectar by creeping under the covering of 

 leaves. Plateau concludes that the rays do not act as 

 signals, and that the form and bright colors of the capitula 

 of dahlias are not an important influence in attracting 

 insects. 



These conclusions are disputed by Forel, who in the 

 following interesting experiment shows that bees in their 

 visits to covered dahlia heads are guided by both memory 

 and sight. 6 In a dahlia bed containing forty-three floral 

 heads of different colors he covered up twenty-five with 

 grape-leaves bent around them and fastened with pins. 

 Of four others he covered only the discs, while of one he 

 covered the rays, leaving the disc visible. The bees were 

 so numerous that at times there were two or three to a 

 flower. The bees ceased at once to visit the completely 

 covered heads; they continued, however, to fly to the 

 heads with only the discs covered, though they immedi- 

 ately abandoned them, except in a few instances where 



•Plateau, F. Note sur l'emploi de recipients en verre. Bvl. Acad, roy., 

 Bruxelles, No. 12, pp. 741-75, 1906. Vid. pp. 771-2. 



•Forel, August. Ants and Some Other Insects, translated by William 

 Morton Wheeler. The Open Court PubUshing Co., Chicago. 



