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Roth and Stay — Cockroaches 
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the oocytes. Three mated bisexual form females that failed to retract 
their oothecae also formed the second egg case in 30.3 ±2.7 days. 
Three mated females that had their oothecae removed 2, 5, and 7 days 
after oviposition ovulated again in 32 to 33 days. Both strains of 
Pycnoscelus are similar in that the presence of an ootheca in the uterus 
inhibits the development of the oocytes. 
Leucophaea maderae: The oothecae were removed from 102 preg- 
nant females at different stages in pregnancy to determine the time 
required for the next ovulation. Forty-three females oviposited during 
the period of the experiment and these results are plotted in figure 1 1 . 
As in Pycnoscelus the time required to ovulate after removal of the 
ootheca varied with the age of the ootheca when it was removed ; the 
younger the ootheca the longer it took to mature the oocytes. Of the 
remaining females, 45 showed little or no growth of the oocytes; those 
whose oothecae were removed O to 1 8 days after ovulation had oocytes 
i.o6d=o.03 mm. (N=22), 62 to 82 days later and 23 females whose 
AGE (DAYS) OF OOTHECA WHEN REMOVED FROM UTERUS 
Fig. 11. Relationship between the age of the ootheca at the time it was 
removed from , the uterus of Leucophaea maderae and the time required to 
form a new egg case. The points plotted at 82 to 97 days on the x axis are 
for females that gave birth normally; all of the other females had their 
oothecae removed manually. Each point represents one female. 
