FERTILIZATION IN THE HONEY-BEE 229 
The penis of the drone (text fig. 1, a) is elaborately adapted 
to this manner of mating. It is a hollow tube, ectodermal in 
origin, non-muscular, growing by invagination from the ninth 
segment of the abdomen. Three main functional regions can 
be identified; the penis tube proper (a), the enlarged bulb at 
its anterior end (6), and the ejaculatory duct (c), leading from 
the bulb to the mesodermal sexual organs. The penis tube, 
proximal to the external opening, is of relatively large diameter; 
Text fig. 1 Diagram of one half of drone sexual apparatus, viewed from the 
medial side, showing the unpaired penis and ejaculatory duct, and the right 
members of the paired mucous glands, seminal vesicles, and testes of a mature 
drone. Internal anatomy of base of gland and vesicle shown as in optical sec- 
tion. The parts have been slightly displaced in mounting on the slide, in order 
to view them all in the horizontal plane; i.e., the anterior portion of the ejacu- 
latory duct lies normally between the two glands, not below one of them; the tip 
of the other gland, joining the one figured at 7’, extends dorsally at about right 
angles to this one, and not in the horizontal plane with it, and the vas deferens at 
h bends around the base of the gland so as to bring the seminal vesicle lateral to 
the gland rather than dorsal. a, penis proper; b, bulb of penis; c, ejaculatory 
duct; d, body of gland; e, seminal vesicle; f, vas deferens; g, testis; h, lower vas 
deferens leading to basal transverse pocket of gland, 7, to which is applied the base 
of the cone-shaped end of the ejaculatory duct, 7; k, slender muscle attaching the 
gland to the posterior abdominal wall; 1, valve of muscle covered with glandular 
epithelium, which guards and partially surrounds the orifice of the vas deferens 
and partially divides the lumen of the gland proper from the basal pocket into 
which opens the vas deferens, and which upon contraction of the gland’s muscu- 
lature divides these regions completely; m, that portion of the gland’s lumen 
which pushes out into the angle of the gland dorsal to the opening of the vas 
deferens; n, blind end of the ejaculatory duct. 
