1964] 
Roth — Reproduction in Cockroaches 
199 
stimuli in controlling the rate of oocyte development because both 
stimuli are usually required in N. cinerea and L. maderae for 
activating the corpora allata to their fullest extent so that the oocytes 
mature at their maximum rate (Roth, 1964). 
In N. cinerea , the growth of the oocytes remain inhibited during 
most of the gestation period (Roth and Stay, 1962b). The female 
remains sexually unreceptive during gestation and will not mate. 
She may or may not mate again after parturition (Roth, 1962). 
Obviously, a pregnant female, or one that has given birth, differs 
physiologically from a virgin female or one that has mated but not 
yet oviposited. This report concerns the control of, and factors 
affecting sexual receptivity and oocyte development during gestation 
and after parturition. 
MATERIALS AND METHODS 
Nauphoeta cinerea was the principal species used, but several 
experiments were also performed on L. maderae , and the bisexual 
and parthenogenetic strains of Pycnoscelus surinamensis (Roth and 
Willis, 1961). The insects were reared and maintained on Purina 
dog chow or laboratory chow. Methods for testing receptivity, 
determining corpus allatum activity, operating on females, and 
laboratory conditions are given in Roth (1964). 
To determine the effect of uterine pressure on oocyte development, 
artificial odthecae made of glass rods or beads were inserted in the 
brood sacs after the odthecae were removed manually. To reduce 
the size of the odtheca, various numbers of eggs were removed from 
the females of N. cinerea as odthecae were being formed (Roth and 
Hahn, 1964). Other techniques are described in their appropriate 
sections in the text. Numbers following ± are standard errors of 
mean values. Unless otherwise indicated, parturition refers only to 
birth of the first litter. 
RESULTS AND CONCLUSIONS 
Mechanism of inhibition of the oocytes during gestation 
The growth of the oocytes during gestation in N. cinerea is shown 
in figure 1. Gestation may last 35-50 days. After 35 days of 
pregnancy, the oocytes in different individuals may vary considerably 
in length. Many females may have oocytes that contain large 
amounts of yolk prior to or at the time of parturitition. 
When the odthecae are removed from pregnant females, the 
oocytes mature prematurely, indicating that an inhibitory influence 
