Diagnostic description.

Female. Body size 7.8 (7.2–8.3) mm, ovipositor length 7.5 (6.9–7.7) mm, fore wing length 7.1 (6.2–7.1) mm (Fig. 57); colouration head and mesosoma black, antenna, legs and metasoma orange, ovipositor sheath dark brown, wings hyaline except for indistinct, apex 1st marginal and 4th submarginal cell (Fig. 58G), hind wing veins spectral; head shape quadrate, width 1.5 (1.1–1.2) × length, postocular space 0.6 (0.5–0.6) × eye length in dorsal view (Fig. 58C), raised transverse carina above toruli absent, malar space 0.3 (0.2–0.3) × height of eye (Fig. 58A); length of scape 1.4 (1.1–1.5) × length of pedicel, 1st flagellomere 1.5 (1.2–1.5) × length of scape, 0.6 (0.5–0.6) × 2nd flagellomere; mesosoma length 1.6 (1.4–1.6) × height, mesoscutum in lateral view rounded antero-dorsally (Fig. 58D); mesoscutum length 0.9 (0.9) × width in dorsal view (Fig. 58E); medial lobe with transverse carinae; ovipositor guide oblique, positioned distally (Fig. 58F); ovipositor sheath length 1.1 (1.0–1.2) × fore wing length (Fig. 57); 2-Rs+M 1.0 (0.9–1.1) × 1-Rs+M, three hamuli, equidistant (Fig. 58G); metasoma pyriform,T1+T2 length 2.3 (2.3–2.8) × width in dorsal view.

Males. Body size (10.0–11.3) mm, similar to females except flagellomere two to tip and variable amounts of metasomal T4 to tip black.

Aulacus leai is similar A. boonanghiensis in general appearance but can be separated by A. leai being larger in size, 7.2–8.3 mm (4.5–5.2 in A. boonanghiensis), metasoma orange (orange except for T4 to tip black in A. boonanghiensis) and only found in Tasmania (northern NSW for A. boonanghiensis)