200 THE METHOD OF DARWIN. 



and an insect would inevitably remove the pol- 

 linia if it inserted its head into one of them. 

 But he had not clung closely enough to his 

 general principle. Darwin himself accepted 

 the correction of his inference as follows : 

 "Delpino, with much sagacity, foresaw that 

 some insect would be discovered " to remove 

 the pollinia by entering the labellum by its 

 large opening, and crawling out through one of 

 the orifices near the anthers; "for he argued 

 that if an insect were to insert its proboscis, as I 

 f had supposed, from the outside through one of 

 the small orifices, the stigma would be liable 

 to be fertilized by the plant's own pollen; and 

 in this he did not believe, from having con- 

 fidence in what I have often insisted on, 

 namely, that all the contrivances for fertiliza- 

 tion are arranged so that the stigma shall 

 receive pollen from a distinct flower or plant. 

 But these speculations are now superfluous ; for, 

 owing to the admirable observations of Dr. H. 

 Miiller, we know that Cypripedium calceolus, in 

 a state of nature, is fertilized in the manner 

 just described." 



Darwin's error in this case consisted in not 

 considering one of the important elements of 

 his principle of adaptation for cross-fertiliza- 

 tion, namely, the importance, not only of 



