T ii E 



North Aiiiericaii Eutomologist 



Editor: A. R. GROTE. rublishers: REINECKE & ZESCH. 



liulfdlo Society of Natural Sciences. 500 Main Street, BulValo, N.Y. 



Vol. 1. IVOVEI^XKER, ISrO. TSo. S. 



On the Fertilization of Yucca. 



Bv Thomas Meeiiax, 



I'rofessor of Botany to Penn. Sta'e Board of Agrlcultuiv. 

 Kciul bc'i'ori! llio saiatoya meeting of tlic American Association for the advaneemoiit 



of Science. August, laVJ. 



Ill thu tnuusautioiis of tlic Academy of Science of St. Louis of 

 Apiil loth 1873, our distinguished jissociate Dr. George Engelmiinn has 

 some "notes on the genus Yucca" in which occurs the following pas- 

 sage: "The conspicuously papillose termination of the pistil had al- 

 ways been considered the stigma, but closer examination showed its 

 papillae to be epidermal ai)pendages, corresponding to similar ones 

 on the lllaments, and entirely destitute of stigmatic function ; never 

 did tliey contribute to the development of a pollen grain occasionly 

 adhering to them. Dr. Mellichamp's notice of a drop of glutinons 

 li({uid in the tube formed by the coalescense of the so-called stig- 

 mas, led me to further experiments, 'iliat tube proved to be the 

 real stigma, exuding stigmatic li(pior, and insects must be the agents 

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

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

 of a new genus of Lepidoptcra — Proiiuha yuccHselhi — and which has 

 proved to be the insect agent which fertilizes the llower. In the 

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

 says '"Avith her maxillary tentacle, so wonderfully modified for the pur- 

 pose, she collects the pollen in large i)ellets, and holds it under the 

 neck and against the front trochanters. In this manner she some- 

 times 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 riglit over its 

 mouth. In this })Osition she works with a vigor, that would indicate 

 combined pleasniv and jiui-posf — moving her head and l)ody from 

 side to side, and apparently making every effort to force the ])ollen 

 into the tube. Such is the method l)v which our Yuccas are fertilized," 



