ROSA ACICULARIS. 



35 



the comparative effect of reducing the attractive surface of the corolla, 

 10 such flowers were grouped with 10 normal ones. Table 15 shows the 

 visitors during an hour of observation. 



Table 15. — Visitors to normal and reduced flowers. 



In accordance with the rule, the reduction of the corolla surface greatly 

 decreased the attractiveness of the rose, since there were three times as 

 many visitors to the normal flowers. 



Stamens masked. — The stamens of 10 flowers were masked with a 

 veil of cotton and 10 normal blossoms left for comparison. Two hours of 

 observation gave the results shown in table 16. 



Table 16. — Visits to normal and masked flowers. 



Andrena madronitens landed on the veil of cotton, walked over it, and 

 finally slipped under the edge to the stamens. A second bee tried the 

 same method, but failed to find them. Bombus proximus and 3 individuals 

 of B. bifarius inspected the masked flowers, but did not stop at them. 

 Where the cotton had slipped a little at the edge exposing the stamens, 

 proximus landed in the flower, but its legs became tangled in the cotton 

 and it flew away as though frightened. 



ARTIFICIAL AND PAINTED FLOWERS. 



Crepe-paper corollas. — The corollas were replaced by artificial ones 



of red, green, and yellow crepe-paper, resembling the normal in size and 



form. The crepe flowers were paired with normal ones in the various 



positions on the bush. Bouquets of flowers in bottles of water were sus- 



