DEVELOPMENT 153 
Tracheze.—The trachee begin as paired invaginations of 
the ectoderm (Fig. 201, t) ; these simple pockets elongate and 
Fic. 197. 
Diagrammatic sagittal sections to illustrate invagination of germ band in Calop- 
teryx. a, anterior pole; ac, amnion cavity; am, amnion; b, blastoderm; d, dorsal; 
g, germ band; h, head end of germ band; p, posterior pole; s, serosa; v, ventral; y, 
yolk.—After Branprt. 
Diagrammatic sagittal sections to illustrate revolution of Calopteryx embryo. a, 
antenna; am, amnion; 7, labium; /'/8, thoracic legs; m, mandible; mx, maxilla; s 
serosa.—After Branpt. 
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