

D 



FIG. 148. Pollination of an orchid (Cypripedium) by a bumblebee. A, bee forcing its 

 way into the flower ; B, obtaining nectar within the flower ; C, bee escaping brushes 

 pollen upon the stigma of the flower; before finally escaping the bee receives another 

 load of pollen from the anther. (From Coulter after Gibson.) 



