276 G. H. BISHOP 
The orifice of the vagina remains tightly closed. If the mem- 
branous floor of the genito-anal vestibule is depressed further, 
however, the median ridge of the bursa is pulled ventrally, and 
the V-shaped lower lip of the vaginal opening is drawn away 
from the base of the sting. The inflation of the bursal pouches, 
by the eversion into them of the drone’s pneumophyses, and 
especially by the withdrawal of the pneumophyses as the eversion 
of the rest of the organ proceeds, would pull the whole ventral 
wall of the bursa ventrally, and the median ridge would draw 
the lower vaginal margin away from the upper, thus opening the 
vaginal orifice to the drone’s organ. The function of the pneu- 
mophyses thus appears to be performed upon their withdrawal 
from, as well as by their eversion into the bursal pouches. This 
would allow the tubular portion of the drone organ which precedes 
the bulb (fig. 2, a) to penetrate the vagina, thus allowing con- 
nection even though the bulb itself should not succeed in everting. 
That this relatively massive bulb enters the vaginal orifice 
at all is doubtful. In the first place, its size relative to the 
dimensions of the vagina (fig. 1, B and C) seems to render this 
impossible, even though one allows for considerable elasticity 
in the walls of this region. But other evidence also renders this 
improbable. As the penis extrudes, the ventral side being longer 
than the dorsal, the organ bends dorsally. ‘This is especially 
noticeable at the tip, the dorsal curvature of which is occasioned 
by the eversion of the bend by which the bulb of the penis (fig. 
2, C) tapers into the ejaculatory duct (at c’). This recurved 
tip will fit neatly into the upward bending copulatory bursa 
and vagina. If this condition obtains in copulation, the bulb 
of the penis with its chitinous plates obviously does not enter 
the vaginal orifice at all, but merely forces the tapering end of 
the ejaculatory duct (c’) within the orifice. Further evidence 
that this is the true state of affairs is obtained from the appear- 
ance of queens that return from the mating flight with the drone 
organ attached. Often, I believe generally, the brown chitinous 
plates of the bulb can be seen just within or partly extruding from 
between the anal plates; although the bursa is so large that if 
they lodged, even partly, within the vagina, they must be com- 
