PLATE 1 
EXPLANATION OF FIGURES 
C, D, E, and H Stages of development of the sexual organs of the drone 
(table in text, p. 252). Camera-lucida drawings of whole mounts, to show, in 
opiteal section, changes in size and conformation of the sex organs from emer- 
gence of the imago until sexual maturity. > 18. 
Black shading, muscular envelope; lines and dots, glandular epithelium; 
broken lines, spermatozoa; dots, mucous secretion; cross-hatching, hypodermis 
of ejaculatory duct; lines, chitinous lining of same. c, ejaculatory duct; d, body 
of gland; e, seminal vesicle; f, vas deferens from testis; h, vas deferens leading 
from vesicle to gland; 7, basal region of gland; 7, cone-shaped end of ejaculatory 
duct, applied to 7; k, slender muscle attaching gland to posterior abdominal wall; 
l, muscular valve guarding vas deferens orifice, and partially separating d from 7; 
m, region of lumen of gland extending out into elbow of gland; n, chitinous drum 
over end of ejaculatory duct. 
Legend on figure D applies alike to all. Numbered lines on C and E locate 
cross-section drawings of subsequent figures (q.v.). 
C Drone at time of emergence. Secretion has just commenced in distal por- 
tions of gland and vesicle. 
D_ Drone three days old. The bulbous expansion of distal portion of gland 
as a mucous reservoir is noticeable, and the spiral serration of the vesicular wall 
has extended throughout the organ. 
E Drone five days old. Organs almost mature. Sperm attached to walls of 
vesicle; wall of gland largely resolved into mucus, chitinous end of ejaculatory 
duct attenuated. 
The fixative has stimulated the basal musculature of the gland to slight con- 
traction, without, however, discharging the content of either gland or vesicle. 
The transverse pocket, 7, into which open vas deferens, h, and ejaculatory duct, 
j, is closed off from the distal reservoir of secretion, d, by the valve, /, and the 
ends of the vas deferens and ejaculatory duct are brought almost into appo- 
sition (compare pl. 3, fig. 10). 
H Drone twenty-one days old, basal portion of gland and seminal vesicle. 
Later stages than five days show but slight further modification. The basal por- 
tion of the gland here is not distorted, as in E, but shows normal resting relation- 
ships of the parts. Even at this age the contents of the organs have not been 
discharged into the bulb of the copulatory organ. 
1 to 4 Successive cross-sections of accessory mucous gland and seminal ves- 
icle of drone at stage A, four daysbefore emergence. X24. Located on figure C, 
by lines numbered 1 to 4, respectively. Legend same as for figure D, with addi- 
tion of X, Y; Z, regions of three inner muscle tracts. 
1 Section through branched end of ejaculatory duct, and the basal portions 
of the two mucous glands. 
2 Section through gland just above entrance of the vas deferens. Between 
the area representing the section of the distal portion of the gland’s lumen, m, 
and that representing the basal portion, 7, the black band, /, represents the edge 
of the muscular valve which, on contraction of the basal musculature of the gland, 
closes off the basal portion from the distal mucous reservoir (figs. C and E). 
3 Section at middle of gland. Between X and Y, Y and Z, and Z and X, 
may be seen in cross-section the three channels into which the gland’s lumen is 
modeled by the three muscle tracts, X, Y, and Z. 
4 Section of the gland just anterior to the end of the seminal vesicle, through 
the region of the testis in the abdomen. 
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