part of adult midgut region adult midgut region R4 adult midgut region R4b 2014-06-05T17:29:32Z Subregion at the middle of the adult midgut region R4. It is composed of enterocytes with small apical protrusions. It can be distinguished from the posterior region R4c by gene expression. fly_anatomy.ontology adult midgut P2 region adult midgut posterior 2 region FBbt:00110903