1962 ] 
Roth and Stay — Cockroaches 
201 
Table 6 — Effect of severing the nerve cord on development of the 
oocytes, in Byrsotria females that were carrying oothecae 
DAYS AFTER 
OVULATION NERVE 
CORD WAS SEVERED 
DAYS AFTER 
OPERATION OOCYTES 
WERE MEASURED 
OOCYTES (MM.) 
MEAN dz S.E. 
N 
Virgin Females 
O 1 
56-59 
3 . 69 ±o .39 
4 
18 
27,33 
4.03 =b 1. 1 1 
2 
28 
33 
5.39 
I 
O 1 
43-62 
i. 34 ±O.Oi 
13 
21-27 
33 
1 .39 dz O.07 
4 
Controls ( sham 
operated) 
O 1 
43-57 
i. 37 ±o .02 
7 
Mated Fe?nales 
12, 19 
4 E 43 
6 . 0 ld= 0.02 
2 
27-28 
29-32 
3 . 68 ±o .48 
4 
30-36 
31-32 
5. 02 ± 0.40 
6 
42-44 
32 
5.50+10.71 
3 
21-39 
30-37 
i. 39 d=o .02 
5 
Controls (sham 
operated) 
12 , 30 , 38 
32 , 43 
1.43 ±0.02 
4 
x The nerve cords of these females were severed prior to oviposition 
and therefore they may be considered to have had the cords cut when 
the female was ovipositing. 
freed for the period of the experiment. The oocytes of these females 
measured o. 78 ±o.oi mm. In 3 females the remaining portion of the 
ootheca in the uterus continued to apply pressure on the ovipisitor and 
their oocytes measured 0.7 7 ±0.05 mm. As controls 6 females were 
sham operated, i.e. their oothecae were partly extruded and pushed 
back, without being cut off, into the uterus 11 to 13 days after ovula- 
tion. They all gave birth at 54 to 56 days of age and their oocytes 
measured 0.741+10.01 mm. These experiments indicate that relieving 
the pressure of the ootheca on the gonapophyses during pregnancy had 
no effect on oocyte development. 
One mated female of the bisexual strain that had oviposited normal- 
ly failed to give birth in the usual period of time (53 days). It was 
