part of embryonic/larval midgut embryonic/larval middle midgut larval middle midgut FBbt:00005777 larval acidic region larval acid zone Central part of the embryonic/larval midgut. This region is acidic (Filshie et al., 1971; Shanbhag and Tripathi, 2009). The epithelium of the anterior part consists of alternating copper cells and interstitial cells (Poulson and Bowen, 1952; Filshie et al., 1971; Shanbhag and Tripathi, 2009). Immediately posterior to this is a region of large flat cells (Poulson and Waterhouse, 1960). Posterior to this, the most posterior part of the middle midgut consists of iron accumulating cells (Poulson and Bowen, 1952). mid embryonic/larval midgut FBbt:00001884 fly_anatomy.ontology middle midgut