Taxonomy of the atrata species-group atrata species-group

Diagnosis. The atrata species-group is here defined to include those members of the genus Belonogaster in which the posterior face of the propodeum is entirely finely shagreened and bare, with at most some punctures and setae on the margins (Figs 1F, 2H, 3E, 4H).

Key to the species of the atrata species-group

(The key is mostly based on the females, as the males of Belonogaster atrata and B. levior are currently unknown)

1. Dorsal side of mesosoma with erect black setae of variable length and with short but clearly hair-like pubescence. Integuments of mesosoma, except posterior face of propodeum, with very fine shagreen and silky shiny, bearing distinct and deep sparse punctures........................................................................................... 2

– Dorsal side of mesosoma without black setae, densely covered in dust-like pubescence. Integuments of mesosoma, except posterior face of propodeum, with coarser micropunctures or shagreen, matte, bearing only few scattered indistinct punctures ................................................................................................... 3

2. Mesosoma with bright golden-brassy pubescence, more evident on pronotum and mesoscutum (Figs 2A–B). T 1 longer and slenderer, much longer than mesosoma, subapical expansion barely wider than basal width in dorsal view (Fig. 2A); basal petiole of T 2 longer, length:width 2.4 in male (Fig. 2F) and 2.8 in female (Fig. 2G). Mesosoma and legs extensively marked with ferruginous-red, wings subhyaline with reddish tinge and slightly darker apex.................. B. aurata Richards

– Mesosoma with pale whitish-yellow pubescence (Figs 1B–C). T 1 shorter and more robust, about as long as mesosoma, subapical expansion much wider than basal width in dorsal view (Fig. 1B); basal petiole of T 2 shorter, length:width 1.5 in female (Fig. 1E; male unknown). Mesosoma and legs entirely black or at most scutellum and metanotum red, wings blackish with distinct blue-purple reflections.............................................................. B. atrata von Schulthess

3. Disc of scutellum narrower, 1.55× as wide as long; median longitudinal furrow deep and well-impressed, dividing the disc of scutellum into two gibbosities (Fig. 3E). Scutellum and metanotum shagreened like propodeum, bearing small but deep and well defined punctures (Fig. 3E). Basal pit of propodeum shallow and wide, weakly indicated (Fig. 3E). Basal petiole of T 2 shorter, length:width 1.6 in female (Fig. 3D; male unknown). Mesosoma black, with reduced dark-red markings............................................................................................... B. levior Richards

– Disc of scutellum wider, 1.8× as wide as long; median longitudinal furrow shallow and barely impressed, not clearly dividing the disc of scutellum into two parts (Fig. 4H). Scutellum and metanotum densely micropunctate, bearing very fine and barely noticeable punctures (Fig. 4H). Basal pit of propodeum deep and narrow, well defined (Fig. 4H). Basal petiole of T 2 longer, length:width 1.6 in male (Fig. 4F) and 1.8 in female (Fig. 4G). Mesosoma ferruginous, irregular dark markings on mesoscutum and pronotum only....................................................... B. velutina Selis & Longair, sp. nov.