CHAP. VI COBTANTHES. 177 



by carrying them away, effect a union between two 

 flowers, generally on distinct plants. This can hardly 

 fail to occur in all the many cases in which the pollinia 

 slowly change their position, when removed from the 

 rostellum, in order to assume a proper direction for 

 striking the stigma ; for the insects during this in- 

 terval will have had time to fly from the flowers on 

 rue plant which will serve as the male, to those 

 <n another plant which will serve as the female. 



