antenna with 12 segments; sides of propodeum and also, but less thickly, the dorsal areas, the base of the rest of the gaster, both below and above, clothed with a dense, whitish, flocculent pubescence; occipital margin on lower side of head bordered with a narrow fringe of woolly pubescence. (Maxillary palpi extremely short, hardly, visible, 2 segmented (Synacra brachialis_); eyes bare, polished, indistinctly faceted, shorter than the distance between on of them and the tip of the antennal socket (as seen from side); no closed radial cell in macropterous species; petiole slightly transverse, smooth; propodeum without a keel on external side of spiracle; scape showing on one side at apex a distinct membranous angulation; hind wing without a closed class/show/5307">basal cell (cf. fig. 1))
antenna with not less than 14 segments; propodeum without dense, flocculent pubescence; base of tergite 2 with at most a thin tuft of pubescence on each side; occipital margin without a fringe of pubescence at sides though there may be on above. (Half the apical circumference of the scape raised to form rim or flange, each extremity of which forms an angular projection; this feature less well developed in Synacra_; maxillary palpi long, well developed, conspicuous, 5-segmented (_Rhyncopsilus apertus)