第十九章 昆虫的胚胎发育 第二节胚胎发育的过程 zygote nucleus cleavage nucle blastode vitellophages pole cells ctodem mesoderm endoderm neuroblasts epidermis mesodermal midgut resorbed germ and bands cells derivatives central nervous splanchnic somatic mesoderm mesoderm system visceral skeletal fat body genital muscles muscles ridges oogonia or gonad spermatogonia 图194 昆虫胚胎发育过程中的器官形成