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Psyche 
[December 
yolk is deposited in the oocytes while the female still has an ootheca 
in the uterus. Engelmann believed that in L. maderae inhibition of 
the corpora allata during pregnancy was due to a humoral factor 
from the eggs in the ootheca (Engelmann, 1957a, b), and mechanical 
stimulation of the genital apparatus by the egg case, plus a “non- 
specific” substance from the uterine eggs (Engelmann, 1960a). 
More recently (Engelmann, 1964) he suggests that inhibition is 
caused by a specific or nonspecific agent released by the egg case or 
the brood sac; this agent acts on neurones in the ventral nerve cord 
and brain which influence regions in the brain that in turn inhibit 
the corpora allata. Roth and Stay (1959, 1961, 1962a, b) concluded 
that mechanical stimuli alone resulting from the stretched uterus 
could account for inhibition of the corpora allata during pregnancy. 
The experimental inhibition of the corpus allatutm by introducing 
glass oothecae in the uteri of N. cinerea and P. surinccmensis does 
not support Engelmann’s last hypothesis. Engelmann (1964) con- 
cluded from his observations on L. maderae that the insertion of an 
artificial ootheca into the uterus reduces the female’s food intake. 
Since fasting or reduced food consumption inhibits the corpora allata 
and egg development, he questions the conclusion, based on the 
insertion of an artificial ootheca, that inhibition of the corpora allata 
by the ootheca is exclusively by a nervous pathway. Although this 
may be the case in L. maderae J the oocytes in P. surinamensis that 
have wax oothecae inserted in their uteri, mature after nerve cord 
transection (see figs. 13 A, B, in Roth and Stay, 1962b) and do 
not mature if the nerve cord is intact. It is true that in most 
pregnant females of N. cinerea the oocytes do not mature if their 
oothecae are removed very early in gestation and the individuals are 
then starved (tables 11, 12). However, the oocytes of females 
which have their oothecae replaced by a glass tube <24 hr. after 
oviposition eventually develop almost to maturity like normal preg- 
nant controls (fig. 3) ; this would not have occurred if the glass 
oothecae had prevented feeding. The lack of oocyte development 
during pregnancy in N. cinerea and P. surinamensis can be explained 
by the hypothesis that mechanical stimulation alone, resulting from 
the presence of the ootheca in the uterus, inhibits the corpora allata. 
Roth and Stay (1962a, b) have suggested that pressure changes 
resulting from the increasing size of the ootheca in the uterus tend 
to prevent or retard adaptation of mechanoreceptors, or the central 
nervous system, so that the corpora allata are inhibited during most 
of the gestation period. In Blaberus craniifer Burmeister, Byrsotria 
