~ 366 
It may be well right here to look a little more closely into the minuter 
characteristics of the Yucca flower at this stage of its development, 
that we may understand more fully the action and influence of the moth. 
In my first article, published some twenty years ago, announcing the 
discovery of Pronuba and its action on Yucca pollination, I was strongly 
inclined to the idea that the act of pollination had some compensating 
inducement to the moth, aside from the impelling instinct of perpetua- 
tion of the species. At that time it was supposed that the stigmatic 
liquor was nectarian, and the conclusion was justifiable that the moth, 
Fie. 65.—Nectar apparatus of Yucca: a, longitudinal section of pistil, with duct (d) and gland (9); 0, 
cross section about middle, showing same parts: ¢, still more enlarged cross section of nectar appa- 
ratus; e, structure of septal gland—after Trelease; h, longitudinal section of top of pistil, showing 
stigmatic tube (s) ovarian cell (0 2), ovule (0), funiculus (f), placenta (p), and tibro-vascular tissue (ft). 
attracted to it for feeding purposes, would incidentally induce pollina- 
tion. On this view of the matter it did not require a great stretch of 
the imagination to conceive that the pollen might also incidentally ac- 
cumulate in the spines, and that the vigorous action of the head that 
had been noticed might even be considered as an effort to get rid of the 
incumbrance while feeding. In those days I was more imbued with the 
common notion that lower creatures are impelled for the most part un- 
consciously to their acts. Twenty years of study and experience have 
only served to prove the acts of Pronuba the more unselfish and with- 
