Diagnostic Description.

Female. Body size 8.1 mm, ovipositor length 6.5 mm, fore wing length 8.6 mm (Fig. 75A); colouration head and mesosoma black except scape, pedicel, mandibles, clypeal margin orange, flagellomeres 4–8 pale orange, legs orange except coxae dark-brown, metasoma orange except for small amount of black anteriorly on T1, segments 3–8 brownish, ovipositor sheaths black; wings hyaline, distinct infuscation of distal quarter of 1st marginal and distal half of 4th submarginal cell (Fig. 76G), hind wing veins largely spectral; head quadrate, width 1.5 × length, postocular space 0.4 × eye length in dorsal view (Fig. 76C), raised transverse carina above toruli absent, malar space 0.4 × height of eye (Fig. 76A); length of scape 1.6 × pedicel length, 1st flagellomere 1.2 × length of scape, 0.5 × 2nd flagellomere; mesosoma length 1.7 × height, mesoscutum in lateral view truncated antero-dorsally (Fig. 76D), length 0.8 × width in dorsal view (Fig. 76E); medial lobe transverse carinae; ovipositor guide oblique, positioned distally (Fig. 76F); ovipositor sheath length 0.8 × fore wing length (Fig. 75A); fore wing vein 2-Rs+M 1.1 × 1-Rs+M, vein Cu pigmented, four hamuli equidistant (Fig. 76G); metasoma pyriform, T1+T2 length 1.9 × width in dorsal view.

Male. Body size (9.2) mm, similar to female except antenna black (Fig. 75B).

Aulacus smithi is superficially similar to A. walkeri but can be separated by the pale-orange colouration on antenna flagellomeres 4–8 (flagellomeres dark brown in A. walkeri), head wider, 1.5 x length (A. walkeri 1.0 x length), malar space longer 0.4 x height of eye (A. walkeri 0.2 x height of eye), ovipositor longer 0.8 x fore wing length (A. walkeri 0.6 x fore wing length).