CONSPICUOUS FLOWERS RARELY VISITED BY INSECTS 157 



pea visited a few times by females of Bombus fervidus only; but 

 in other seasons I have occasionally observed honey-bees endeav- 

 oring to find nectar in the flowers. The visits of the bumble- 

 bees were made in the legitimate way, but I was unable to approach 

 near enough to determine whether the carina was actually 

 depressed or not. In each instance, the bee visited only three 

 or four flowers, probably because it experienced difficulty in 

 obtaining the nectar which was not abundant. 



In this connection, it is a matter of surprise that Plateau 

 passes over the flowers of the sweet pea, Lathyrus odoratus L., 

 without mention. This species belongs to the same family as 

 the garden pea, to which it is closely allied in form and structure, 

 though differing in details. Although the blossoms have a strong 

 and pleasant odor suggestive of honey in addition to the most 

 brilliant hues, it is yet more sparingly visited by insects than the 

 garden pea. According to Plateau, the nearly scentless flowers 

 of the garden pea require an agreeable odor to attract insects; 

 but the fragrance of the sweet pea, which is so pleasing that any 

 effort to improve it would be as futile as the proverbial attempt 

 to paint the lily, does not give the inflorescence any permanent 

 advantage over that of the garden pea. If the absence of insects 

 from the garden pea shows that the influence of its coloration 

 is of no significance, then it may be inquired does not the absence 

 of insects from the sweet pea prove that both color and odor are 

 of no importance ? Bees neglect to visit the sweet pea frequently 

 not because these two allurements are of no benefit, but because 

 they have learned from experience that they can not obtain 

 nectar. To attract numerous visits, both the garden pea and 

 the sweet pea require an available food supply. 



Place a honey-bee on one of the wings of the sweet pea, and it 

 is at once apparent that it is neither large enough nor strong 

 enough to depress the carina. Repeated examinations of the flow- 

 ers continued through several weeks of the summer of 1912 

 failed to reveal a single visit by any species of bee. But by 

 September 22, the autumnal honey-flow from the golden-rods 

 was over, and the honey-bees were at liberty to give more 

 attention to the few other flowers still remaining in bloom. On 

 this date I repeatedly saw honey-bees alight and examine the 

 flowers of the sweet pea, but they made no attempt to depress 

 the keel. One probed diligently between a wing petal and the 



