ERRONEOUS DEDUCTION. 199 



In the work on the Fertilization of Orchids 

 Darwin's sagacity found full play in the inter- 

 pretation of the structure of orchids in ac- 

 cordance with the principle of adaptation for 

 cross-fertilization. Confident that all the mar- 

 vellously complex structures of orchidaceous 

 flowers were adaptations for cross-fertilization, 

 he regarded each case only as presenting a 

 question with regard to the particular mode of 

 the mutual action of the insect and the flower 

 organs. He was frequently able to predict this 

 mutual action in the case of particular species. 

 He never for a moment lost faith in the prin- 

 ciple; but in at least one case he went wrong in 

 his interpretation by not applying the principle 

 rigorously enough. 



In the Cypripedium t or Lady's Slipper, there 

 are two small orifices near the anthers and one 

 large opening in the labellum or odd petal. 1 

 After discussing the structure of the flower he 

 said, " Formerly I supposed that insects alighted 

 on the labellum and inserted their proboscides 

 through either of the small orifices close to the 

 anthers " to extract the nectar. This inference 

 seemed plausible enough; the small orifices 

 seemed well adapted to accomplish cross-fertil- 

 ization because they were close to the anthers, 



1 Fertilization of Orchids, pp. 229-231. 



