FURTHER STUDIES OF YUCCAS. 07 



and fell into some other serious errors, he appears to have 

 been the first to observe the collection of pollen by the 

 female Pronuba, though not with the detail given by Pro- 

 fessor Eiley in the account of his own observation of this 

 operation on Y . Jilamentosa .* 



The pollinator of this variety, as of the more representa- 

 tive form of the species, is the white Pronuba yuccasella. 

 As on other Yuccas, the moth is quite sluggish within the 

 flowers during the day, apparently considering itself con- 

 cealed by its protective coloration. Numerous laden females 

 were taken and observed about the flowers at night, and copu- 

 lation within the flower was several times seen in the evening, 

 but I was unfortunately not able to see these moths engaged 

 in either pollination or oviposition. The pale poll en, how- 

 ever, is very evident in the green stigmas, where there is lit- 

 tle reason to doubt they have placed it. Egg punctures were 

 also observed in numbers, in such a situation on the ovary as 

 to show that the moth occupies the same position when ovi- 

 positing as on filamentosa. On the older panicles a fair 

 percentage of fruit was maturing at the time of my exam- 

 ination at Dallas, and showed the usual Pronuba constric- 

 tions, and several capsules of the preceding year which were 

 found had been perforated by escaping larvae, and contained 

 remnants of tunneled seeds. 



At Putnam, Texas, considerably west of Dallas, a larger 

 form of what I take to be this variety of glauca occurs, 

 with narrower leaves ; and about the end of May this was 

 passing out of bloom, just as elata, still further west, was 

 beginning to flower. At this place, fewer capsules had 

 set than about Dallas, but these showed the irregularities 

 indicative of oviposition by Pronuba, which had quite dis- 

 appeared ; and some of the stalks of the preceding year 

 still bore capsules which were marked by the escape 

 perforations of her larvae. 



* Proc. Amer. Assoc. Adv. Science, 1882, xxxL 467-8; Third Garde* 

 Report, 106, pi. 38, f. 2. 



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