198 
Psyche 
[December 
In Blattella pressure on the oothecal chamber by the ootheca ap- 
pears to be responsible for the inhibition of the oocytes, the stimulus 
being transmitted via the nerve cord (Roth and Stay, 1959, 1962). 
When the ootheca is in the uterus of Pycnoscelus the ovipositor 
is bent forward and is held in that position by the egg case. This 
suggested the possibility that the gonapophyses might be involved in 
transmitting nervous stimuli to the brain which then inhibits the 
corpora allata. Two experiments on Pycnoscelus were performed to 
test this hypothesis. Glass beads (3-3.5 mm. in diameter) were insert- 
ed into the vestibule of 7 females 1 to 2 days of age. A small drop of 
ferrule cement on the anal segments prevented the beads from being 
extruded ; the beads exerted pressure on the ovipositor. The oocytes 
were measured at 3 different periods. At 5 days of age they were 1.77 
±0.13 mm. (N=4), at 7 days, 2.20 mm. (N=i), and at 13 days, 
2.85 ±0.01 mm. (N==2). Normal females at 5, 7, and 13 days of 
age had oocytes 2.03 ±0.08 mm. (N=9), 2.28zbo.o8 mm. (N = 
15), and 2.94±0.04 mm. (N=6) respectively. The presence of a 
bead and the resulting pressure on the ovipositor of recently-emerged 
females had essentially no effect on the development of the oocytes. 
To determine if release of pressure by the ootheca on the ovipositor 
during gestation would result in resumption of oocyte development, 
the oothecae of pregnant females were partly extruded, a portion of 
the egg case was cut off and the remainder was pushed back into the 
uterus. This was done to 8 females 11 to 12 days after oviposition 
and their oocytes were measured on the fifty-fourth to fifty-sixth days 
of pregnancy when the females gave birth or parturition was immi- 
nent. Five operations were successful in that the ovipositors were 
Explanation of figure 14 
Fig. 14. Reproductive organs of Byrsotria fumigata. 
A. Normal mated female sham operated (nerve cord) when pregnant 
38 days and dissected after 70 days of pregnancy. The eggs (arrows) in 
the ovaries are undeveloped; U = uterus containing ootheca. 
B. Mated female whose ootheca was removed 40 days after oviposition 
and dissected 32 days later. The eggs in the ovaries have almost matured 
(6.22 mm. long). 
C. Mated female whose nerve cord was severed at 39 days of pregnancy 
and dissected 32 days after the operation (71 days pregnant). The eggs 
(arrows) in the ovaries have nearly matured (5.88 mm. long) ; U — uterus 
containing ootheca. 
D. Virgin female allatectomized at one day of age. After 52 days, cor- 
pora allata from two females 9 to 10 days of age were implanted. Oviposition 
occurred 28 to 35 days after implantation of corpora allata. The eggs 
(arrows) in the ovary are almost full grown (5.88 mm.) although an ootheca 
remains in the uterus (U). 
E. Ovary of a virgin female 43 days old. The oocytes are large and 
degenerating (A-D= : X2; E ZZ X4). 
