FERTILIZATION IN THE HONEY-BEE 239 
main axis of the abdomen. Its posterior margin is the valve 
projecting from the dorsomedial side of the lumen. Below this 
valve, the second region consists of a small flat pocket lying 
across the base of the gland (text fig. 1 and pl. 1, 7). Into this 
pocket and from the valve’s posterior surface opens the vas 
deferens (h). Applied ventrally to this pocket is the expanded 
end of the corresponding branch of the ejaculatory duct (J). 
This flattens out into the base of a cone, whose wall does not 
break through into the gland’s lumen, although the gland’s wall 
is penetrated by the blind end of this duct (pl. 3, figs. 9 and 10). 
The relation of the parts therefore admits of the following 
hypothesis as to its functioning. If the flat pocket is collapsed, 
the edge of the valve is pressed close against the opposite side 
of the gland’s lumen, shutting off completely the whole basal 
region of the gland from the sac full of mucus (pl. 1, fig. E, and 
pl. 3, fig. 10). The mouth of the vas deferens is applied at the 
same time exactly over the flattened blind end of the ejaculatory 
duct. If this be burst through, the result is a passageway through 
this system of organs extending through the vas deferens, seminal 
vesicle, lower vas deferens to the basal region of the gland, and 
out through the ejaculatory duct. It extends past the body of 
the gland as if the latter’s content were not to be discharged 
with the content of the seminal vesicle; although in develop- 
ment the gland and vas deferens form a continuous tube, a tube 
whose lumen is closed off from the lumen of the ejaculatory 
duct by a membrane of chitin over the blind end of the latter. 
A consideration of the musculature of the region further points 
to this manner of functioning. 
2. The muscle layers. The ejaculatory duct has no muscles 
in its wall; it is a single-layered tube of ectodermal origin invagi- 
nated from the hypodermis and chitinized on the inside. The 
vas deferens, seminal vesicle, and gland have two muscle layers, 
outer longitudinal and an inner circular layer, forming a continu- 
ous envelope over the whole of these organs. Running from the 
base of the gland half or more its length distally, a third or inmost 
muscular layer, consisting of three separate tracts of fibers, has 
been described (pl. 1, figs. 1 to 4, x, y, z). A closer analysis of 
