154 ENTOMOLOGICAL SOCIETY 
referring to the insect as " a white moth of the genus Tortrix," and in a 
subsequent communication (ibid., August, 1872, p. 37) he corrected the 
error and recorded some further facts in the life-history of the insect. In 
neither case was there any claim of individual discovery of the entomo- 
logical facts, and these announcements must be read in the light of his 
subsequent more deliberate language which I have quoted. 
In conclusion, having already devoted more time to Mr. Hulst's opinions 
than they justify, let me add that another year's study of Yucca fertilization 
has not only served to confirm all that I have hitherto written, but still 
further to enhance the importance of Pronuba to the plant and the intelli- 
gent nature of her unique performances. Prof. Wm. Trelease, who has 
made the only other careful observations on the subject which have come to 
my notice, has demonstrated (Bull. Torrey Bot. Club, Aug., 1886, pp. 135- 
141) that the stigmatic liquor is not nectariferous, but that the slight 
amount of nectar associated with the flowers is secreted in thin pockets 
formed by the partitions that separate the three cells of the pistil, and 
which open externally by a contracted pore from which the nectar is poured 
through a capillary tube (enclosed by the closely applied, but not out- 
wardly united, lobes of the ovary) to the base of the pistil, so that nectar- 
feeding insects seek it not about the stigma, but at the base of the pistil 
or of the petal*, whether within or without. I have fully verified Tre- 
lease's statements by dissection and study of the insects seeking this scant 
nectar, and endorse his conclusion that while the observations serve to 
disprove any positive value of their nectar in the pollination of Yucca 
flowers, they add to the importance of Pronuba by showing that the acts 
of collecting the pollen and transferring it to the stigma are performed 
voluntarily and without food compensation as I was at first inclined to 
believe. 
I have lately had the pleasure of studying Yucca -whipplei in California 
and the remarkable tree-yucca ( Y. brevifolia) in the Mojave desert. The 
former is pollinized by Pronuba maculata Riley, and the latter by a most 
remarkably modified and adapted species which I expect to describe as 
Pronuba paradoxa. 
Thus everywhere in the United States where Yucca nominally fruits we 
find it associated with its Pronuba. 
I await with interest and curiosity any new discoveries in this connec- 
tion, but, so far as present knowledge justifies anticipation, I should ex- 
pect, where neither Pronuba nor Pronuba-like insect exists, to find the plant 
modified to more readily permit self-fertilization sooner than to find Apis 
mellifica the pollinizing agent, the opinion of Mr. E. L. Layard, of 
New Caledonia (who first expressed it in 1880; Nature, vol. xxii, p. 606), 
and of Mr. Hulst, to the contrary notwithstanding. 
On board the "City of Rome," Aug. 22, 1887. 
