part of develops from mesothoracic tibial preapical bristle fly_anatomy.ontology VFB:FBbt_00004391 FBbt:00004391 T2 PAB Longer and thicker bristle without bracts in the anterior compartment, on the dorsal distal region of the mesothoracic tibia, near the joint with the first tarsal segment. It is part of the longitudinal bristle row 5. mesothoracic tibia microchaeta mesothoracic leg mechanosensory bristle presumptive mesothoracic tibial preapical bristle