"58 
ORTHOPTERA. 
Eggs are laid in the forms of a capsule, (fig. 9) a brown hard structure 
of characteristic form containing a considerable number of eggs. In 
Periplaneta americana, out of seven egg-capsules, four contained 16 
eggs, two contained 18 and one only 12. Each capsule consists of a 
Fig. 9.—Styloygia rhqmbifolia. 
Adult female and egg-case. 
double row of cigar-shaped eggs, surrounded by a chitinous coating 
which is joined by a wavy line which runs along the one end of the 
rows of eggs ; when the eggs hatch, this line opens, allowing the young 
emerge. It is probable that the expansion of the eggs before hatching, 
a common phenomenon, is the cause of the opening of the egg-capsule, 
but it is also stated that the cement joining the edges is softened by a 
fluid secreted by the embryo just before hatching. The egg-capsule 
is not always deposited by the female as soon as formed, but is in some 
species carried in the oviduct almost until hatching ; in a few foreign 
species this habit is carried to the extreme, and the eggs are carried till 
the young hatch. An egg cluster of Periplaneta americana laid on the 
2nd July, hatched on 27th July and the nymphs were only half-grown at 
