part of abdominal segment 7 larval abdominal segment 7 spiracular histoblast nest abdominal spiracular histoblast nest abdominal 7 FBbt:00001833 fly_anatomy.ontology Histoblast nest of abdominal segment 7. It forms an attachment between the epidermis and the spiracle in the larva (Hartenstein, 1993) and generates the spiracle and perispiracular epidermis of the adult during metamorphosis (Ninov et al., 2007).