91 
One copulation apparently fertilises all the eggs pro- 
duced by the female. It is obvious, when one compares 
the male with a mature female (Plate L., figs. 1 and 2), 
that fertilisation cannot be accomplished when the female 
genital segment is fully developed. Hence the need of 
it being effected at an early stage. 
The exact period at which the eggs are fertilised by the 
spermatozoa is unknown. The spermatophores may be 
found attached to the body for some time after the female 
has begun to produce eggs (Plate IT., fig. 4, sp.), but they 
are then simply empty sacs. Plate Il., fig. 7, shows a 
pair of spermatophores that have been detached from an 
egg-bearing female. The little opening at d. was in 
direct communication with the vulva. These sacs were 
empty. In an immature female (Plate II., fig. 6), the 
vulva leads into a short vagina, passing directly into the 
oviduct. The spermatozoa probably remain in the vagina 
‘ 
which becomes a “ receptaculum seminis.” In: transverse 
or longitudinal sections through the region of the vagina 
of a mature female masses of spermatozoa are frequently 
found in the swollen part (Plate I1., fig. 4, rep.). The 
oviduct in the immature female has no communication 
with the exterior except through the vulva. 
The ovary of a mature female appears as shown in 
Plate IIL., fig. 10. It consists of a number of tubules 
lined with nucleated cells representing a germinal epithe- 
hum, which will form the eggs. The interior of the 
tubules is filled with a granular substance, staining faintly 
blue with hematoxylin and eosin. When the eggs become 
mature the walls of the tubule break down and the eggs 
pass out into the oviduct. They are then very small, about 
‘)2 mm. in diameter, and do not fill up the duct. Thev 
are simply nucleated cells. As they pass posteriorly they 
increase in size. In the fourth thoracic segment they 
