in.] THE FERTILISATION OF FLOWERS. 



53 



the insect must alight on the labellum, and in push- 

 ing its proboscis down the nectary, strikes its head 

 against the pollinia, which, being sticky at their 



FIG. 66. 



bases, become attached to the insect's head. Owing 

 to the weight of the pollen and the slenderness of the 

 stalks they gradually lose their erect position and 



FIG. 67. 



FIG. 68. 



assume one more horizontal, so that on visiting 

 another flower the pollinia strike exactly against the 



stigmas. 



In a foreign species (Catasetwti) certain 



