1962] 
Roth and Stay — Cockroaches 
187 
J2. Oocytes develop but at a slower rate and to a lesser degree than 
in fed females (N auphoeta ) . 
3. Oocytes develop at a normal or slightly slower rate than fed 
females (Blaberus craniifer , Byrsotria ) . 
4. Oocytes mature about as rapidly asTed females ( Diploptera , 
Pycnoscelus surinamensis — bisexual and parthenogenetic 
strains). 
Inhibition of the corpora allata during pregnancy 
During the first gestation the basal oocytes, in all of the species in- 
vestigated in this study, usually remain undeveloped except for a small 
increase in length ; some N auphoeta females may have oocytes con- 
taining yolk at parturition. Yolk deposition occurs in these basal 
oocytes only after parturition (except in Diploptera and some N au- 
phoeta) . This has already been pointed out in Pycnoscelus (fig. 1). 
Very similar cycles occur in Blattella (Roth and Stay, 1962), Leu- 
cophaea (Engelmann, 1957) and Diploptera (Engelmann, 1959; 
Roth and Stay, 1961). However in Diploptera the oocytes begin to 
show deposition of yolk about 3 days before parturition (Engelmann, 
1959; Roth and Stay, 1961). Although complete ovulation cycles are 
not given for Blaberus, Byrsotria , and N auphoeta, measurements of 
the new oocytes at ovulation, and at parturition show that inhibition 
of the corpora allata during gestation also occurs in these forms. In 
Leucophaea (Engelmann, 1957, i960), Diploptera (Engelmann, 
1959 ; Roth and Stay, 1961), and Pycnoscelus (Roth and Stay, 1959) 
removal of the ootheca results in resumption of growth of the oocytes 
prematurely, indicating that the ootheca in the uterus, in some man- 
ner, inhibits the activity of the corpora allata. The following experi- 
ments were performed to investigate the nature of inhibition of the 
corpora allata during gestation. 
Pycnoscelus surinamensis: The odthecae were removed from 84 
females of the parthenogenetic strain, 62 (74%) of which subsequent- 
ly ovulated. Of the 22 females that failed to oviposit 25 to 37 days 
after the operation, 15 had oocytes that showed essentially no develop- 
ment (0.64 to O.79 mm.) and 7 had oocytes with definite yolk deposits 
(0.84 to 2.39 mm.) ; one female had oocytes that had apparently 
matured but had not been laid and were being resorbed. There is an 
inverse relationship between the age of the ootheca at the time it is 
removed from the uterus and the time required to ovulate again. 
Less time is required to ovulate again, the older the uterine eggs are 
when removed (fig. 10). This relationship also has been found in 
Blattella and Diploptera (Roth and Stay, 1961, 1962). One 
