42S HABITS OF INSECTS. CHAP. XI. 



certain fixed points, which made it easy to measure the 

 time taken in passing from one place to another. 



Witn respect to the number of flowers which bees 

 visit in a given time, I observed that in exactly one 

 minute a humble-bee visited twenty-four of the closed 

 flowers of the Linaria cymbalaria ; another bee visited 

 in the same time twenty-two flowers of the Symphori- 

 earpus racemosa ; and another seventeen flowers on two 

 plants of a Delphinium. In the course of fifteen 

 minutes a single flower on the summit of a plant of 

 (Enothera was visited eight times by several humble- 

 bees, and I followed the last of these bees, whilst 

 it visited in the course of a few additional minutes 

 every plant of the same species in a large flower- 

 garden. In nineteen minutes every flower on a small 

 plant of Nemophila insignis was visited twice. In one 

 minute six flowers of a Campanula were entered by 

 a pollen-collecting hive-bee ; and bees when thus 

 employed work slower than when sucking nectar. 

 Lastly, seven flower-stalks on a plant of Dictamnus 

 fraxinella were observed on the 15th of June 1841 during 

 ten minutes ; they were visited by thirteen humble-bees, 

 each of which entered many flowers. On the 22nd the 

 same flower-stalks were visited within the same time by 

 eleven humble-bees. This plant bore altogether 280 

 flowers, and from the above data, taking into con- 

 sideration how late in the evening humble-bees work, 

 each flower must have been visited at least thirty times 

 daily, and the same flower keeps open during several 

 days. The frequency of the visits of bees is also some- 

 times shown by the manner in which the petals are 

 scratched by their hooked tarsi ; I have seen large beds 

 of Mimulus, Stachys, and Lathyrus with the beauty 

 of their flowers thus sadly defaced. 



Perforation of the Corolla ly Bees. I have already 



