B. olba

- metasomal segments 1-3 entirely O-Y
- T4-6 broadly transversely Y apically
- S2 process large, rounded below, concave behind
- mesopleura Y above, B below (including venter)

image courtesy Kerry Stuart: https://inaturalist.ala.org.au/observations/342858697

B. olba

- metasomal segments 1-3 entirely O-Y
- T4-5 broadly transversely Y apically (T6 not visible here)
- S2 process large, rounded below, concave behind
- wings subhyaline (not heavily infuscated)
- mesopleura Y above, B below (including venter)

image courtesy Jean and Fred Hort: https://inaturalist.ala.org.au/observations/68527581

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. wilcannia

- T1-3 broad orange bands apically, B basally
- clypeus entirely black
- mesopleura & venter black
- S2 process small, angulate

image courtesy LGJ: https://inaturalist.ala.org.au/observations/337896162

B. wilcannia

- front basitarsus with 6 pecten spines
- front tarsomeres 3 & 4 with strong apical flanges beneath

image courtesy LGJ: https://inaturalist.ala.org.au/observations/337896162

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