202 Wisconsin Academy of Sciences, Arts, and Letters. 
ventral edge of the eighth segment. On the left side of the abdom¬ 
inal cavity lies the seminal receptacle (fig. 9, s.r.), a thin-walled 
sac, narrowed at each end and containing the spermatozoa. These 
can be readily seen through its walls in cleared whole mounts of 
the insect and in sections, and the thinness of its walls precludes 
the possibility of glandular structure. From the posterior end of 
the seminal receptacle a slender, delicate duct (fig. 9, d.) leads to 
the vagina, entering it midway between the point of union of the 
oviducts and its opening to the outside. No accessory glands are 
present in Troctes. 
In older individuals than the one represented in the figure, the 
eggs are found in later stages of development. However no insect 
was found with more than one fully developed egg at a time. This 
egg is so large before laying that it occupies fully one-third of the 
abdominal cavity; in insects mounted in glycerine an outer chorion 
and yolk granules can be seen. In ovarian tubules on the other 
side of the abdomen from the well-developed egg, other eggs show 
considerable development, but none equal in size to the first. 
Though careful search was made during the breeding season, no 
eggs were ever found after they were laid. 
The Male Reproductive System 
The most conspicuous structures of the male reproductive sys¬ 
tem are not the testes, but the paired seminal vesicles (fig. 13, v.) 
which lie a little to the left of the median line of the abdomen. 
These are large, when fully matured extending nearly to the 
thorax, and they lie so close to each other as often to give the ap¬ 
pearance of a single organ. An examination of transverse sec¬ 
tions, however, proves it is a paired organ, its parts joining to 
form a single large duct at their proximal ends. This, the ejacula¬ 
tory duct (fig. 13, e.d.), leads to the outside of the body through 
the copulatory apparatus (fig. 13, c.a.). The testes (fig. 13, t.) are 
round or oval bodies lying near the lateral abdominal walls. From 
a surface view they give the impression of being a mass of coiled 
tubes, and when sectioned, they appear to be separated into areas, 
representing coils, which contain the spermatozoa at different 
stages of development (fig. 12, s.). The central portion of ea^h 
testis is formed of spermatogonia, and the posterior portion, from 
which the vas deferens (fig. 13, v.d.) arises, is filled with spermato¬ 
zoa. At each end of the testis is a darkly staining mass (fig. 12, 
