THE WORK OF FLO WERS 299 



garden it happened that Parsnip and Chickory grew 

 side by side, the blue flowers of the one mingling 

 with the yellow flowers of the other. In this case 

 I have watched with interest the striking difference 

 in the behavior of bees and flies. The bees were 

 abundant on the blue flowers, but in several hours 

 of watching not a single bee was seen to alight on 

 a yellow flower, although they would often spring 

 over one to get at the next blue flower. On the 

 other hand, the yellow flowers fairly swarmed with 

 flies of different species, while not a single one ap- 

 peared on the blue flowers. 



We must take into account, in this connection, a 

 peculiarity which the bee has of visiting, as a rule, but 

 one kind of a flower at a time. I have often per- 

 formed the experiment of placing a branch of the 

 blue - flowered Thyme (of which the bees are very 

 fond) in a bed of Yellow Lupine, in which they were 

 busily at work. They avoided the Thyme uniformly, 

 going over it or around it to get at the Yellow 

 Lupine flowers. But, on placing a cluster of Lupine 

 flowers in a bed of Thyme blossoms, they paid no 

 attention to it. 



Flowers which display no conspicuous sign -boards 

 are, nevertheless, visited eagerly by bees or other 

 insects (e. g., Grape, Virginia Creeper, Mignonette 

 English Ivy, etc.). It appears quite certain that it is 

 the odor which attracts them in these cases. Night- 



