DEVELOPMENT 149 
folding over the germ band from either side, as shown in Fig. 
190, and at length the two folds meet and unite to form two 
membranes (Fig. 191), namely, an inner one, or amnion, and 
an outer one, or serosa. 
Fic. 192. 
B 
Germ band of a beetle, Melasoma, in three successive stages. A, unsegmented; 
B, with oral segments demarkated; C, with three oral, three thoracic and two ab- 
dominal segments.—After GRABER. 
Segmentation and Appendages.—On the germ band, 
which represents the ventral part of the future insect, the body 
segments are marked off by 
transverse grooves (Figs. 
192, 194) ; this segmentation 
beginning usually at the an- 
terior end of the germ band 
and progressing backward. 
Furthermore, an anterior in- 
: ee Es Diagrammatic sagittal section § of 
Oo TS (ye t & 
folding pccute (Fig. 193), hymenopterous egg to show stomodzal 
tormung the stomodeum, (s) and proctodeal (~) invaginations 
‘ of the germ band (g).—After GRABER. 
from which the mouth, 
pharynx, cesophagus and other parts of the fore gut are to 
arise; a similar, but posterior invagination, or proctodeum 
