Term Name:	primary branching, open tracheal system
Synonyms:	primary tracheal branching
Definition:	Formation of primary branches in the open tracheal system. These form from small groups of cells that migrate out at specific positions, organizing into tubes as they migrate. An example of this is found in Drosophila melanogaster.
Ontology:	GO: Biological Process [GO:0007428]    QuickGO    AmiGO