1962] 
Roth and Stay — Cockroaches 
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val between age at mating and age at ovulation when older females 
mated (Engelmann, i960). Engelmann suggested that this shorten- 
ing of the period needed for egg maturation could be explained by the 
presence of larger amounts of reserve substances that would allow for 
more rapid growth of the eggs and might not be due to the presence 
of larger oocytes at the later mating. Our findings confirm Engel- 
mann’s in that Leucophaea tend to mate more readily when their 
oocytes reach a certain size. However, some females mate even though 
their oocytes have grown beyond this critical size and the shortening 
of the period between mating and ovulation is undoubtedly due to the 
presence of large oocytes in these older females ; some females mate 
even when there is a high titer of corpus allatum hormone (as indi- 
cated by large oocytes). 
Engelmann (i960) found that when the nerve cord of Leucophaea 
was severed o to 2 days after mating, oocyte maturation occurred 
about a week later than normal mated females. When the cord was 
severed 3 to 19 days after mating, the females oviposited at the same 
age as normal mated females indicating that an intact nerve cord is 
necessary for at least 2 days after mating for the mating stimulus to 
be effective. When the nerve cords of virgin females were severed 
and they were not mated, ovulation occurred at the same time as 
females that had their nerve cords severed O to 2 days after mating. 
Engelmann concluded that severance of the ventral nerve cord in 
virgins either stimulates the corpora allata or cuts off an inhibitory 
center for the corpora allata but he favored the latter hypothesis. 
We severed the nerve cords of females prior to mating them and 
found that in most cases the spermatophore was not inserted properly. 
Of 27 females that mated after their nerve cords were severed, only 
8 had spermatophores that were apparently transferred by the male 
normally. Four females had spermatophores that were visible in the 
genital region but they had not been inserted properly in the bursa. 
In one mating the spermatophore was dropped by the male without 
being transferred to the female. Fourteen females had no spermato- 
phores after mating and originally it was believed that none had been 
transferred by the male. However, it was discovered that in some 
females the male pierced the wall of the uterus and inserted the sper- 
matophore in the body cavity near the right ovary (fig. 13C). This 
was found in 7 females but may have occurred in 6 others that appar- 
ently had no spermatophore inserted but were not dissected because 
we did not realize that the spermatophore could be inserted into the 
body cavity. One female had no spermatophore after mating, based 
on dissection. It seems that the female takes an active role in the 
