Diagnostic description.

Aulacus kiwarrakensis can be distinguished from other Australian species based on the distinctive black and orange colouration, vertex with reddish-brown patches on eye margin of vertex and broad band of orange sub apically on ovipositor sheath.

Female. Body size 8.4 (7.0–8.5) mm, ovipositor length 6.5 (4.9–6.5) mm, fore wing length 8.0 (7.1–8.1) mm (Fig. 55A); colouration head and mesosoma black, vertex with reddish-brown patches on eye margin, antenna orange except flagellomeres 11 and 12 black, orange patch on malar space, legs orange, metasomal T1 and T2 orange with remaining segments black, ovipositor sheaths with broad band of orange sub apically; wings hyaline except for wings hyaline, fore wing with distinct brown infuscation apically on 1st marginal and 4th submarginal cell (Fig. 56G), hind wing veins spectral; head shape quadrate, width 1.5 (1.4–1.6) × length, postocular space 0.4 (0.4) × eye length in dorsal view (Fig. 56C), raised transverse carina above toruli absent, malar space 0.3 (0.3) × height of eye (Fig. 56A); length of scape 1.5 (1.5–2.5) × length of pedicel, 1st flagellomere 1.2 (1.1) × length of scape, 0.5 (0.5–0.6) × 2nd flagellomere; mesosoma length 1.9 (1.7–1.9) × height, mesoscutum in lateral view angular antero-dorsally (Fig. 56D); mesoscutum length 0.9 (0.8–0.9) × width in dorsal view (Fig. 56E); medial lobe transverse carinae; ovipositor guide oblique, positioned distally (Fig. 56F); ovipositor sheath length 0.8 (0.7–0.8) × fore wing length (Fig. 55A); 2-Rs+M 1.9 (1.8–1.9) × 1-Rs+M, three hamuli, equidistant (Fig. 56G); metasoma clavate,T1+T2 length 1.9 (1.8–2.0) × width in dorsal view.

Males. Body size (8.0–9.8) mm, similar to females except flagellomeres dark brown (Fig. 55B).