402 WHEELER. (Vor. If. 
all other cases the capsule was regularly turned to the right, 
never to the left. 
The female Periplaneta orientalis drops the capsule soon after 
its completion, with predilection in some food supply, such as 
flour or meal. Slatta germanica carries it for about a month, 
then drops it shortly before the hatching of the larve. Some 
writers claim that the parent assists the young in escaping from 
the capsule, but I have proved by many experiments that the 
expanding and struggling of the young insects are amply 
sufficient to separate the feebly united lips of the crista. Such 
an instinct in the female would be of use only if the lips of the 
capsule could not be opened by the young. Taschenberg (46) 
claims that the female regularly lays only one capsule and dies 
soon after its deposition. My observations on fifty females, 
whose wings were clipped as soon as they had formed their first 
capsule, have convinced me that they certainly lay two perfect 
capsules as a rule, and possibly more, in the course of the 
year. 
As will be seen from the preceding account, it is a very easy 
matter to orient the eggs of the capsule, to tell just what 
position any odthecal egg held in the ovary, or just what position 
any egg in the ovary will hold in the capsule. The germarium 
pole of the ovarian egg lies just beneath the crista after oviposi- 
tion. The concave side of the curved sausage-shaped ovarian 
egg is turned to the wall of the capsule, and its convex face, on 
which the embryo will appear with its head towards the crista, is 
turned to the interior of the capsule and faces the corresponding 
surface of the opposite egg. The micropyles which pointed 
away from the germarium are on the convex face of the ova- 
rian, and on the inner face of the odthecal egg, and point down- 
wards away from the crista. 
THE DEVELOPMENT OF THE EGG TO THE FORMATION OF THE 
BLASTODERM. 
Blatta. 
The odthecal egg of A/atza, like the ovarian egg, is glistening 
white. The latter has been described as sausage-shaped, but 
the pressure exerted by the eggs on one another in the capsule 
alters their original form very considerably. They assume the 
