196 
Psyche 
[December 
Table 4 — Effect of nerve cord severance on oocyte development in 
the parthenogenetic strain of Pycnoscelus surinamensis 
DAYS AFTER 
OVIPOSITION NERVE 
CORD WAS SEVERED 
DAYS AFTER 
OPERATION 
OOCYTES WERE 
MEASURED 
OOCYTES (MM.) 
MEAN ± S.E. 
N 
<1 
24 
2 .08 ± 0.07 
3 
4 
25 
2.94 
1 
<1 
26 
2.57=1=0.30 
2 
o 1 
29 
3.06 2 
1 
<1 
31 
3.52zbo.i6 2 
2 
<1 
32 
2.94 
1 
27-32 
23-33 
Oocytes matured 
5 
Controls 
and degenerating 3 
(sham operated) 
1-4 
25 
0.67=b0.0i 
4 
<1 
29 
0.65 ±0.02 
4 
1 
38 
o. 66 ±o .02 
5 
1 Operated on just after the female retracted the ootheca. 
2 Oocytes matured. 
3 The uterine eggs of these females were completely developed and 
parturition was imminent. The eggs began to hatch (fig. 12A) from 
3 of the 5 females after their oothecae were removed from the uterus. 
when the nerve cords were severed in five females that had been carry- 
ing a wax “ootheca” in the uterus for 24 days, the oocytes were well 
developed (fig. 13B) 8 to 13 days later (table 3). 
The effect of nerve cord severance in pregnant females on develop- 
ment of the oocytes is shown in table 4. The oocytes could mature 
(2.97 to 3.36 mm., table 1), in females carrying oothecae once the 
nerve cord was severed. The time required for the oocytes to mature 
in pregnant nerve-cord-severed females was essentially the same as 
that taken by females after their oothecae were manually removed. 
When removed at O days a new ootheca was formed in about 28 to 31 
days. When removed after 27 to 32 days of pregnancy ovulation 
occurred about 22 to 25 days later (fig. 10). The five females that 
had their nerve cords severed 27 to 32 days after oviposition all had 
mature oocytes that were degenerating or being resorbed 23 to 33 days 
later at the time the uterine eggs were ready to hatch (fig. 12A). 
Apparently oviposition could or did not occur while an ootheca was 
