1953] 
Nutting — Reproduction in Blaberus 
11 
ootheca protruding about two-thirds of its length from the 
brood sac. Some of these females were segregated, and 
their oothecae were usually completely returned into the 
brood sac within a short time. This act apparently signals 
the completion of an ootheca and the beginning of the 
incubation period, as has been observed in Gromphadorhina 
by Chopard (1950). Neither the duration of gestation nor 
the span of female reproductive life is known for any of 
the species of Blaberus, although the former may last for 
more than two months. Females sometimes discard an 
ootheca; this has occurred most notably after the roaches 
have been disturbed and handled during cage-cleaning. 
Except in two cases noted below, none of these oothecae 
has been known to hatch. 
Recently a relatively inactive female was found with 
about half the length of her ootheca extruded from the 
brood sac. At least the pro- and mesothorax of each visible 
embryo were free of the ootheca. The ensuing events of 
hatching were observed under a low-power dissecting micro- 
scope. All of these embryos were rapidly swallowing air, 
and the bubbles could easily be seen passing through the 
head capsule into the enlarging crop. Within 2 or 3 min- 
utes the embryonic cuticle on one individual had split; 
after 60 to 90 seconds, with some side to side struggling, 
it was free. Although the abdominal movements of the 
female indicated that she was trying to expel the ootheca, 
she was unable to extrude more than three-fourths of its 
length. I therefore removed the egg case, and within 10 
minutes all but four unfertile eggs had hatched. 
On becoming free the embryos gradually stopped swal- 
lowing air; at this point they were cylindrical and about 
10 mm. long. They began telescoping their abdominal seg- 
ments and within a few seconds they had assumed a flat- 
tened roach-like appearance measuring about 7 mm. long. 
The air is probably expelled through the mouth. The young 
roaches do not leave the mother but swarm over the ootheca 
practically consuming it in a short time. Saupe (1929) 
suspected the mother of devouring the oothecal remains. 
A degree of maternal solicitude is exhibited by this roach, 
for many times I have observed the female to remain 
