The subgenus Orphnabaccha is distinguished by having the metasternum pilose, anterior anepisternum pilose, facial tubercle well-developed and metaespisternum bare.
Vockeroth (1969) divided Orphnabaccha in three species groups based on abdomen shape and male genitalia. The coreuleus group have black and grey abdomen, black face, darkened costal area and infuscate apical wing. The amplus group has a typical Syrphus-type abdominal pattern and furcate superior lobe of the male genitalia. The caldus group is more variable but members share yellow face with medial black vitta and abdominal yellow markings.