YUCCA MOTH AND YUCCA POLLINATION. 135 
the nest of pointed blades. At the same time an egress is 
afforded the liberated spermatozoa through the mouth of 
the duct —the only point not constricted by the radiating 
fibers — and once within its walls a successive contraction of 
its muscular fibers, like the vermicular action in the small 
intestines of mammals, would cause their ready descent to 
the oviduct. Thus the spicules not only serve to liberate 
the spermatozoa, but also to facilitate their egress through 
the attached base, where the spermatophore wall is thinnest. 
THE OVIPOSITOR. 
We have already seen, in the characterization of what 
may be called the external parts of the ovipositor, that it 
consists apparently of two principal joints, the basal part, 
when highly magnified, showing an imbricato-granulated 
surface, the granulations strongest basally, and diminishing 
_ distally, and each having a more or less distinctly marked, 
retrorse point, while the terminal part is smooth and ends 
in a delicate dorsal, chitinous saw and a strong serrate tip. 
It is the working of the ovipositor, however, by the 
rods connected with it to which I wish to draw more par- 
ticular attention here. On carefully dissecting the abdo- 
men, there are seen along the dorsal integument four large, 
distinct, tough, longitudinal muscular bands. Viewing 
them ventrally each is seen to be inserted upon the widened 
free end of aslender, brown, horny rod, strongly attached, 
by an accumulation of muscular tissue, to the base of the 
vagina. The two inner rods (PI. 37, Fig. C, 7, 2) are 
nearly parallel, the outer two slightly divergent (*, k). 
When the ovipositor is withdrawn the two inner rods extend 
back beyond the others and reach to the base of the third 
abdominal joint or even somewhat beyond. These two 
inner rods converge to form the lateral walls of the ovi- 
positor proper, extending as dark streaks to its extreme 
tip. The ovipositor is therefore a continuous piece, and 
in reality not jointed, though appearing so from the dif- 
ferent sculpturing of the basal and terminal covering. 
