Diagnostic description.

Aulacus bamagensis is an easily recognised species based on the combination of the unique conical head shape in dorsal view (fig. 8C), long post ocular space and short malar space in lateral view (fig. 8A).

Female. Body size 8.3 (7.4–8.3), ovipositor length 4.5 (4.1–4.5), fore wing length 5.5 (4.6–5.5) (Fig. 7); colouration mostly black, except mandibles cream-coloured, scape and pedicel brown, fore and mid legs brown, tibiae and tarsi white except 5th tarsomere and claw brown, hind legs black, tarsus cream-coloured, metasomal T2–T3 orange, ovipositor sheaths black except for broad band cream-coloured band sub apically; fore wing hyaline, lightly infuscated on apex 1st marginal and 4th submarginal cell (Fig. 8G), hind wing veins spectral; head shape conical, width 1.2 × length, postocular space 0.6 (0.5–0.6) × eye length (Fig. 8C), occipital carina present laterally, raised transverse carina above toruli absent, malar space 0.1 × eye height in lateral view (Fig. 8A); scape length 1.4 × pedicel length, 1st flagellomere 1.1 (1.0–1.1) × scape length, 0.5 × 2nd flagellomere; mesosoma length 1.7 × height (Fig. 8D), mesoscutum in lateral view rounded antero-dorsally, length 1.1 × width in dorsal view (Fig. 8E); medial lobe reticulate; ovipositor guide oblique, positioned medially (Fig. 8F); ovipositor sheath length 0.8 (0.8–0.9) × fore wing length (Fig. 7); fore wing vein 2-Rs+M 1.1 × 1-Rs+M, three hamuli equidistant (Fig. 8G); metasoma clavate,T1+T2 length 7.0 (7.9) × width in dorsal view.

Variation. The extent of orange colouration on the metasoma is reduced to a small patch on T2 in the specimen from Kuranda QLD.

Although this species is superficially similar to A. rieki in general appearance, they can be easily separated on the shape of the head in dorsal view, conical in A. bamagensis and quadrate in A. rieki, and coloration of metasoma (no orange in A. rieki).