1883.] Entomology. 197 
OBSERVATIONS ON THE FERTILIZATION OF YUCCA AND ON 
STRUCTURAL AND ANATOMICAL PECULIARITIES IN PRONUBA AND 
Propoxus.\—This paper records some recent experiments and 
observations which establish fully and conclusively the fact that 
Pronuba is necessary to the fertilization of the capsular Yuccas. 
It describes for the first time how the pollen is gathered and col- 
lected by the female Pronuba. The act is as deliberate and won- 
derful as that of pollination. Going to the top of the stamen she 
stretches her tentacles to the utmost on the opposite side of the 
anther, presses the head down upon the pollen and scrapes it to- 
gether by a horizontal motion of her maxilla. The head is then 
raised and the front legs are used to shape the grains into a pellet, 
the tentacles coiling and uncoiling meanwhile. She thus goes 
from one anther to another until she has a sufficiency. 
My observations confirm the accuracy of Dr. Geo. Engelmann’s 
conclusion as to the impotence of the stigmatic apices in some of 
the Yuccas, and show how the apparently contradictory expe- 
rience of Mr. Meehan can be reconciled on variation in this re- 
Spect in the species of the same genus. : 
The exceptional self-fertilization in Yucca aloifolia—the only 
Species in which it is recorded—is shown to be due to the fact 
that in the fruit of these species there is no style, the stigma be- 
ing sessile, and the nectar abundant, filling and even bulging out 
of the shallow opening or tube. The flowers are always pendu- 
lous and the pollen falling from anthers can, under favorable cir- 
‘cumstances, readily lodge on the nectar. 
_ The irregularity in the shape of the fruit of the Yuccas—con- 
sidered a characteristic by botanists—is proved by experiment to 
be due to the punctures of Pronuba. 
~- the egg of Pronuba, which averages 1.5™™ long, having a 
Swollen apical end, anda long and variable pedicel, is passed into 
the ovarian cavity of the fruit. The puncture is made usually 
just below the middle of the pistil on the deeper depression 
which marks the true dissepiment, or through the thinnest part 
of the wall. The horny part of the ovipositor reaches the longi- 
tudinal Cavity at the external base of the ovule near the funicu- 
us, without, as a rule, penetrating or touching the ovule itself; 
and the delicate and extensile oviduct then conveys the egg for 
Some distance (the length of six or eight seeds) along the cavity, 
g terminal portion of the oviduct being furnished with retrorse 
hairs which help to hold it in place during the act. 
< p e paper concludes with some studies of the internal anatomy 
of Pronuba and Prodoxus. 
~ Natura Sucarinc.—Lepidopterists have long found sugaring, 
on the besmearing of tree trunks with various, more or less in- 
_ toxicating, Sweets one of the best means of obtaining night-fly- 
es the ch rel paper, by Professor C. V. Riley, read at the Montreal Meeting of 
