BOTANICAL GAZETTE. 243 



has some "notes on the genus Yucca" in wliich occurs the following 

 passage: "The conspicuously pa|)illose termination of the pistil had 

 always been considered the stigma, but closer examination showed 

 its papillae to be epidermal appendages, corresponding to similar 

 ones on the filaments, and entirely d3stitute of stigmatic function ; 

 never did they contribute to the development of a pollen grain occa- 

 sionally adhering to them. Dr. Mellichamp's notice of a drop of glu- 

 tinous liquid in the tube formed by the coalescense of the so-called 

 stigmas, led me to further experiments. That tube prov,ed to be the 

 real stigma, exuding stigmatic liquor, and insects must be the agents 

 which introduced the pollen into the tube." Subsequent investiga- 

 tions by our esteemed associate Professor Riley, led to the discovery 

 of a new genus of Lepidoptera — Pro)iuha yaccnsella — and which has 

 proved to be the insect agent which fertilizes tlie flower. In the • 

 same number of the Proceedings, Prof. Riley describes this insect 

 and says "with her maxillary tentacle, so wonderfully modified for 

 the purpose, she collects the pollen in large pellets, and holds it un- 

 d^ the neck and against the front trochanters. In this manner she 

 sometimes carries a mass twice the size of her head. Thus laden she 

 clings to the top of the pistil, bends her head, thrusts her tongue into 

 the stigmatic nectary and brings the pollen-masses right over its 

 mouth. In this' position she works with a vigor, that would indicate 

 combined pleasure and purpose — moving her head and body from 

 side to side, and apparently making every effort to force the pollen 

 into the tube. Such is the method by which our Yuccas are ferti- 

 lized." 



It may be remembered that at our meeting at Buflfalo I j^roduced 

 three capsules that had not been produced by this elaborate process, 

 but simply by mere touching of the papillose apex with one of ihe 

 flower's own polleniferous anthers. Prof. Riley was so sure that the 

 seed-vessels could not have been produced in that way, that there 

 must have been some insect agency unknown to me in addition to my 

 work, that at the conclusion of my paper he asked permission to cut 

 open the capsules, sure of being able to show the larvae in the fruit; 

 but he found them not. I recall these matters to show that I have 

 not misapprehended the position our friends take on this question. 



I now again exhibit numerous seed vessels from this plant of Yuc- 

 ca angastifolia in which no trace of larvae can be found ; and seed 

 vessels of Yucca filamentosa growing but a few yards from the other, 

 which are infested by the Pronuba yuccaseUa^ as this species always is 

 when it seeds at all. 



