part of develops from develops into stomodeum developing embryonic structure late stomodeal invagination primordium stomatogastric nervous system primordium embryonic frontal ganglion frontal ganglion primordium fly_anatomy.ontology FBbt:00018003 A(n) primordium that develops into some embryonic frontal ganglion. It develops from some stomatogastric nervous system primordium. P1 FrGgl anterior ectoderm derivative