Key to the Iranian species of Diolcogaster Ashmead 1. T1 without a medio-longitudinal sulcus or with a weak and small sulcus (Fig. 4C); vein r-m of fore wing arising from vein r so that areolet is 3-sided (Fig. 4F).......................................................................... 2 - T1 with a strong and long medio-longitudinal sulcus (Figs 6C, 8C, 10C, 12C, 14C); vein r-m of fore wing arising from vein r+3RSa, so that areolet is 4-sided (Figs 6 F–6G, 8F, 10F, 12F, 14F).............................................. 3 2. Head in anterolateral view with a deep depression; antenna very short, without bristly setae; propodeum strongly sculptured, with medio-longitudinal carina; T1 with a medio-longitudinal sulcus anteriorly; T2 with median field. … D. spreta (Marshall) - Head in lateral view without a deep depression (Fig. 3F); antenna long, with bristly setae (Fig. 3B); propodeum largely smooth, with a weak and incomplete medio-longitudinal carina (Fig. 4B); T1 with a medio-longitudinal sulcus shallowly impressed anteriorly (Fig. 4C); T2 without median field (Figs 4 C–4D)................................. D. alvearia (Fabricius) 3. Gena in lateral view slightly smaller than eye width (Fig. 5F); eye medium-sized, its height 2.1× temple length and 3.4× oculomandibular line (Fig. 5D); OD and POL 0.5× and 1.1× OOL, respectively (Figs 5 E–5F); inter-ocular line 3.5× oculo-mandibular line (Fig. 5D); malar space medium-sized, 3.4× eye length (Fig. 5D); T2 width 3.5× its medial length at posterior margin (Figs 6 C–6D); vein cu-a of hind wing curved (Fig. 6G)........................................ D. claritibia (Papp) - Gena in lateral view extremely short (Figs 7F, 11F, 13F); eye very large, its height 7.2× temple length and 13.5× oculo-mandibular line (Figs 7D, 11D, 13D); OD and POL 2.2× and 3.2× OOL, respectively (Figs 7 E–7F, 11E–11F, 13E–13F); inter-ocular line 6.0× oculo-mandibular line (Figs 7D, 11D, 13D); malar space very short, 13.5× eye length (Figs 7D, 11D, 13D); T2 width 2.1× its medial length at posterior margin (Figs 8C, 12 C–12D, 14C–14D); vein cu-a of hind wing straight (Figs 8F, 12F, 14F).................................................................................... D. mayae (Shestakov)

Published as part of Moghaddam, Mostafa Ghafouri, Rakhshani, Ehsan, Achterberg, Cornelis Van & Mokhtari, Azizollah, 2019, A taxonomic review of the genus Diolcogaster Ashmead (Hymenoptera, Braconidae, Microgastrinae) in Iran, distribution and morphological variability, pp. 95-124 in Zootaxa 4590 (1) on page 100, DOI: 10.11646/zootaxa.4590.1.4, http://zenodo.org/record/2651658