1962] 
Roth and Stay — Cockroaches 
1 8 1 
proper positioning of the spermatophore in the bursa copulatrix, and 
an intact nerve cord is needed for proper muscular movements of the 
female genitalia. Of 1 1 nerve-cord-severed virgin females that ovi- 
posited 7 dropped their egg cases when they were formed and 4 re- 
tracted the ootheca into the uterus but aborted some time later. 
Blaberus craniifer: The growth of the oocytes of virgins is rapid 
but mating affords sufficient additional stimulation (fig. 9) so that 
ovulation occurs about a week earlier than in unmated individuals 
(fig. 4). Eighteen mated females oviposited in 19 to 29 days (x= 
23.9±0.6 days) ; sixteen oviposited normally, 1 dropped its ootheca 
and 1 failed to retract the egg case completely. Virgin females ovi- 
posited in 18 to 41 days (x=32.0d=o.8 ; N = 36). Stimulation from 
mating results in either an additional production of gonadotropic hor- 
mone or it may possibly serve as an oviposition stimulus. The relation- 
ship of age at mating and age at oviposition of the female is similar to 
that found in Byrsotria (fig. 3). The older the female when mated 
the shorter the interval to ovulation indicating that the oocytes of 
these older females are large when mating occurs. 
Of 40 virgin females that oviposited 23 (58%) failed to retract the 
egg case completely and some of the eggs protruded beyond the abdo- 
men. This may be due to the fact that in some females the eggs are 
not aligned properly in the ootheca and may even be arranged in 3 
rows (rather than 2) which may make it difficult to retract the egg 
case completely into the uterus. Generally, in most virgin females that 
ovulate, the proper amount of colleterial gland secretion does not flow 
out over the eggs since the accessory glands are usually quite full even 
after the egg case is formed. Sometimes not all of the eggs are laid 
and mature oocytes remain in the ovaries and are eventually resorbed. 
Thirteen females retracted the ootheca normally into the uterus. Four 
females dropped the ootheca although some eggs remained in the 
uterus. Perhaps this is related to the lack of proper amount of col- 
leterial gland secretion being poured out around the eggs; the result 
may be the formation of a weak ootheca which cannot support the 
weight of the eggs as they are extruded some distance beyond the end 
of the abdomen prior to their being retracted. In addition to the above 
40 females, 5 unmated females that did not oviposit in 46 to 51 days 
had oocytes that had obviously matured (based on size) but were 
degenerating. 
Six allatectomized virgin females that had not ovulated had cor- 
pora allata implanted at 62 to 82 days of age; all 6 oviposited within 
31 days after implantation. Nine allatectomized virgin females kept 
for 66 to 238 days failed to ovulate. 
