part of develops from mesothoracic bristle katepisternal bristle FBbt:00004321 sternal bristle Bristle of the mesothoracic episternum or katepisternum. On the dorsal aspect there are 5 to 8 bristles, with 1 to 3 of them being very large (Bb-). In the ventral aspect there is an isolated bristle (I) and in the anterior region there are 2 to 4 yellow bristles (YB). VFB:FBbt_00004321 isolated bristle https://www.ento.csiro.au/biology/drosophila/melanogaster.html?katepisternal%20setulae sternopleural seta yellow bristle Bb- fly_anatomy.ontology https://www.ento.csiro.au/biology/drosophila/melanogaster.html?katepisternal%20setae%20 katepisternum presumptive mesothoracic structures from mesothoracic leg disc