2l6 
Psyche 
[December 
Histograms showing the frequency distributions of the lengths of 
the oocytes at the time of mating of the females used in figure 1 1 
are given in figure 13. Except for females whose oothecae were 
removed 1 - 2 days after oviposition, the greatest percentage of 
females mated when their oocytes were 0.99 - 1 .09 mm. long and 
contained yolk. The basal oocytes of females whose oothecae were 
removed 1-2 days after oviposition are about 0.5 1 mm. long and 
smaller than the oocytes of females whose oothecae are removed at 
21-26 days or 51 - 54 days after ovulation, or at parturition. There 
is an increase in the length of the oocytes during gestation, even 
though the corpora allata are inactive during most of the gestation 
period as indicated by absence of yolk in the oocytes. When the 
ootheca is removed just after ovulation, a certain amount of t’me 
elapses before the oocytes attain the length of those of females whose 
oothecae were removed near the middle or about the end of the 
gestation period. Many females that mated after their oothecae 
were removed 1 - 2 days after oviposition, had oocytes that did not 
contain yolk; but their colleterial glands usually contained some 
secretion. However, not all of the colleterial gland secretion is used 
during the first oviposition so that its presence in the gland after 
parturition cannot be used as an indicator of corpus allatum activity. 
Effect of mating stimuli on return of receptivity 
Females were mated to castrated males. After oviposition their 
oothecae were removed at different periods of gestation, and the 
females were placed with males and checked daily for spermatophores. 
The return of receptivity (table 5) of these females that lacked 
sperm in the spermathecae was similar to that found in normally 
mated females (cf. table 4) ; the longer the oothecae had been in 
the uterus when it was removed, the quicker the females regained 
receptivity. Ten females (room temperature) were allowed to mate 
to completion and had their spermatophores removed 1-2 min. 
after mating so that no sperm entered the spermathecae (Roth, 
1964). After ovipositing (oothecae were aborted and never had 
been in the uteri, or were removed <24 hr. after oviposition) they 
were exposed to males (2 c? cf : i$) for 1 hr. daily to determine 
when receptivity would return. Six of the females mated in 16-28 
days (x = 21.2 d= 1.9) and their oocytes averaged 0.99 d= 0.04 
mm. long. The return of receptivity in these females was similar 
to that of normally mated females rather than virgin females whose 
oothecae were removed (cf. table 4). These experiments show that 
