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Psyche 
[December 
even when their hormone concentration was low. In addition, virgin 
allateetomized L. maderae do mate if they are exposed to courting 
males (Roth and Barth, 1964) ; presumably the corpus allatum 
hormone concentration is very low or nonexistent in these females. 
There may be a decided difference in oocyte size at mating in 
N . cinerea during the first preoviposition period as compared with 
that following parturition. Although virgin females usually mate 
when their oocytes first begin to show yolk deposition, they remain 
receptive (if isolated from males) even though their oocytes continue 
to grow (Roth, 1964). This is also true in L. maderae (Roth and 
Stay, 1962b). Receptivity of females of N. cinerea following partu- 
rition differs in that those with well developed oocytes at the time of 
parturition, or those isolated from males for 2 or more days after 
giving birth (and consequently have large oocytes) are or become 
unreceptive. Virtually all females of L. maderae become receptive 
shortly after birth. In this species the oocytes do not contain yolk at 
parturition (Roth and Stay, 1962b). However, L. maderae is similar 
to N. cinerea in that females usually become unreceptive if they are 
not given access to males a week after parturition. If, as suggested, 
neurosecretion is responsible for receptivity, it appears that the con- 
centration of the hormone is critical only after parturition but not 
during the first precopulatory period (i.e., in the virgin female). 
Perhaps a high titer of neurosecretion does not inhibit receptivity in 
the virgin female but may prevent mating after parturition in once- 
mated females. It has already been shown in N. cinerea (Roth, 
1964) that the effect of a particular reproductive stimulus may vary 
depending on the period in the reproductive cycle in which it occurs; 
for example, uterine stretching inhibits mating and oocyte develop- 
ment after oviposition (i.e., during gestation) but is not effective 
when exerted during the first preoviposition period. 
Ovariectomized virgin females of N. cinerea mate a few days 
after emergence but most of them do not become receptive again 
even 2 months after the initial mating; this is longer than the time 
required for normal gestation. In Leucophaea ovariectomy results 
in hypertrophy of the corpora allata and, as a result, the normal 
cyclical activity of the corpora allata (i.e., active during preovi- 
position and inactive during gestation) does not occur (von Harnack 
and Scharrer, 1956). The ootheca in the uterus is undoubtedly 
largely responsible for the cyclical activity of the corpora allata 
(Engelmann, 1957a, Roth and Stay, 1959, 1962b). It is possible 
that the neurosecretory system of the brain also continues to be active 
