91 



These interesting facts, which I have fully verified, show that 

 nectar-feeding insects seek it not about the stigma, but at the 

 base of the stamens or of the petals, whether within or without. 

 In short, the nectar in these Yucca flowers has no value in pol- 

 lination, and Pronuba, in collecting the pollen and transferring 

 it to the stigma, finds no food compensation, a conclusion which 

 is confirmed by a study of the minute structure and internal 



i. (! Xcct'ir apparatus of Yucca: , longitudinal section of pistil, with duct (d) and 

 gland (g); b, cross-section about middle, showing same parts ; c, still more enlarged 

 cross-section of nectar apparatus; e, structure of septal gland after Trelease ; h, longi- 

 tudinal section of top of pistil, showing stigmatic tube (*) ovarian cell (oc), ovule (o), 

 funiculiis (/), placenta (p), and fibro-vascular tissue (ft)- 



anatomy of the moth, which indicate that the tongue proper, 

 though strongly developed, has to a great extent, if not entirely, 

 lost its function as a sucking organ, and that the alimentary 

 canal is practically functionless, being aborted before reaching 

 the anus. This defunctionization, jf I may use the term, of im- 



