B. olba

- T1-3 entirely O-Y
- T4-6 extensively Y
- mesoscutum with broad, Y discal stripes
- wings subhyaline
- propodeum Y, with black patch anterodorsally

image courtesy Jean and Fred Hort: https://inaturalist.ala.org.au/observations/68527413

B. olba

- 7 pecten spines
- frons extensively O-Y, with limited black across & below ocelli
- mesopleura & venter Y

image courtesy Jean and Fred Hort: https://inaturalist.ala.org.au/observations/68527413

B. aureofasciata

- infuscated wings
- mesopleura black
- T1-2 black with orange markings
- T3 orange mark not reaching sides
- T4-6 entirely black

image courtesy Jean and Fred Hort: https://inaturalist.ala.org.au/observations/68678881

B. aureofasciata

- T1-3 with O-Y markings, T3 narrower & not reaching sides
- propodeum black, with small/limited orange markings

image courtesy Jean and Fred Hort: https://inaturalist.ala.org.au/observations/68678881