YUCCA MOTH AND YUCCA POLLINATION. 133 
ning from the base to the extreme tip (Plate 40, Fig. 2, 
d). There are some seventy or more of the longer 
spicules and other shorter ones; but they vary less in 
length than in other species. In the impregnated female 
there is found within this receptaculum and almost filling 
it, what appears to be an inner sac with a narrow neck 
entering and following the neck of the receptaculum. 
This is doubtless but a combined mass of spermatic par- 
ticles or fasciculi forming what has been called by Lepi- 
dopterists the large spermatophore. The albumen-like 
wall or envelope of this mass is somewhat thickened as it 
approaches the hubs of the receptaculum but then suddenly 
becomes thin and is somewhat insecurely fastened to the 
hubs so that when the spermatophore is detached, there is 
practically an opening in each side at the point where it 
was attached to the receptaculum. There are three mem- 
branes to this receptaculum, an external or muscular, a 
middle or serous, and an internal or mucous. The strong 
fibers of the muscular coat radiate from the border of 
the hub of one of the chitinous bodies, and are inserted 
in a similar position upon that of the opposite side. 
They thus include the whole of the sac until toward the 
neck, where they change to circular constricting fibers, 
and thus continue through the duct. Plate 40, Fig. 1, @ 
gives an enlarged view of this receptaculum, with a longi- 
tudinal section through the hubs at 0, showing the large 
spermatophore or inner sac ¢, and the space between it and 
the walls of the receptaculum, showing the manner in 
which the hub and the radiate spicules are placed at d. 
In Pronuba yuccasella this receptaculum averages about 
1.7 mm. in length, by 1. mm. in diameter, the crusher or 
radiate body measuring 1. mm., the rays averaging 0.43 
mm. in length and the hub or axis 0.14 mm. in diameter. 
By way of exhibiting how very much more strongly de- 
veloped this receptaculum and its crushers are in yuccasella 
than those in any of the other species, I have introduced 
(Plate 40, Fig. 2) drawings of the similar organs of 
