faa! NOTES AND COMMENTS. 323 
of the egg just below the stigma explains the remarkable symmetry 
of most of the fertilised pistils, contrasting with the constriction 
or indentation of the Eastern species at the point where the ovary 
has been punctured. 
In another smaller species, Yucca elata, observed at Eagle Flat, 
Texas, Pyonuba yuccasella was the agent of pollination. When about 
to deposit an egg, the moth, as in Y. filamentosa, runs nervously about 
within the bottom of the flower, then scrambles to the top of the 
pistil and backs down between two stamens by a succession of jerks, 
until her head is about level with the base of the style. Clinging to 
the pistil, she then punctures the ovary, and the egg is consigned to 
its place in the manner so well described by Riley for jilamentosa. 
Usually each oviposition is followed by pollination, but in a few 
cases two eggs were laid before pollen was carried to the stigma, and 
sometimes so disturbed is the moth by the bright light of the 
observer’s lantern, that she will leave a flower altogether without 
pollination. In one such instance her first act on entering another 
flower was to thrust her pollen-laden tentacles into the stigma, though 
it is unusual for this to precede oviposition. On several occasions, 
when disturbed in laying her egg, the moth ran upon a stamen, 
shaking it quite violently and making several passes at the anther 
with her tentacles, as if frightened from one of her occupations only 
to engage in another. The very distinct Californian Yucca Whipplet, 
as Professor Riley has shown, is pollinated by a distinct Pvonuba, 
which he names P. maculata, of a general white colour, but mottled 
with black. In this species the pollen is not loose and powdery, as 
in Yucca proper, but glutinous, and frequent observation has shown 
that it may be deposited on the stigma directly from the anthers in 
closing flowers, so that self-pollination becomes possible, and Mr. 
Coquillet, of Los Angeles, records the seeding, in 1892, of a number 
of panicles which he had covered with gauze before any of the flowers 
opened. Owing to the more open and more diurnal character of the 
flowers in this species, the moth is far more active in the daytime than 
its congeners. Moreover, the resting position, with the head towards 
the stigma, is almost identical with that taken in oviposition, which, 
like pollination, may be witnessed at any time during the day. 
Standing on the side of the pistil the female pierces the ovary at the 
thinnest part. Generally not more than six eggs are laid in one 
pistil—one on either side of each septum—often fewer, so that even 
if they all hatch—an unlikely event—there is rarely more than one 
larva to each tier of seeds, thus allowing a fair percentage to ripen. 
Pollination was well seen in the variety gvamunifolia, where it was 
observed several times under a cloudless sky, the first time at about 
noon. Flying into a flower, the moth runs about the bases of the 
stamens in the usual way, then quickly clambers upon the inner side 
of a filament, and, with the tentacles stretched over the pollen masses, 
drags first one and then the other out of the anther cells, pressing 
Y2 
