182 
Psyche 
[December 
All the nerves to the corpora allata were severed in 1 1 virgin 
females and the glands were left in the animals; ten oviposited in 
21.8zhO.49 days which is similar to ovulation in mated females. This 
would indicate that the brain tends to inhibit the corpora allata in 
virgin B. craniifer and mating overcomes this inhibition. 
Blaberus giganteus: The oocytes of virgins grow and yolk is de- 
posited but after about a month they may degenerate unless mating 
occurs (fig. 9). In general mating appears to be necessary for comple- 
tion of oocyte development, at least more so than in B. craniifer. 
Fourteen females kept with males until mating occurred, mated at 
8 to 35 days of age and oviposited when 35 to 51 days old (x=42.6 
±1.3 days). Of 8 virgin females, not shown in figure 8, kept for 51 
to 68 days, only 2 oviposited when 51 days old, and in both individuals 
the oothecae were dropped and not retracted ; the 6 females that did 
not oviposit had small abnormally shaped oocytes that failed to de- 
velop. 
The relationship between age when mated and age at ovulation 
(fig. 3) appears to be similar to Byrsotria and B. craniifer rather than 
Leucophaea. The females of B. giganteus which have continuous 
access to males, mate over a rather wide age range, and their oocytes 
may vary considerably in size at the time of mating. 
Thirteen of 14 virgin females that had all the nerves to the corpora 
allata severed at O to 19 days of age ovulated in 35.1 ±1.2 days after 
the operations ; one oviposited 153 days after the operation at 163 days 
of age. Severing the connectives to the corpora allata apparently 
removed the inhibition from the brain. 
The effects of mating vary in degree among the species of cock- 
roaches that incubate their eggs internally or carry them externally 
during the incubation period. In the summary given below, data from 
Engelmann, (1957, 1959, i960), Roth and Willis (1961) Roth and 
Stay (1961, 1962), and the present study have been used. 
I. Effect of mating on oocyte development. 
1 . Oocytes of virgins may degenerate : 
a. before reaching ovulation size (N auphoeta cinerea and 
Blaberus giganteus) 
b. before or after reaching ovulation size (Byrsotria fumi- 
gata) 
Mating prevents degeneration of the oocytes in the above 3 
species. The oocytes of virgins generally do not degenerate in 
Blaberus craniifer (rarely), Diploptera punctata Leucophaea 
maderae, Pycnoscelus surinamensis (parthenogenetic and bi- 
sexual strains), Blattella germanica , and Blattella vaga. 
