Key to genera of the tribe Adeliini Viereck

1. Metasoma smooth, sometimes first metasomal tergite basally sculptured, weakly rugulose or crenulate-rugose (Figs 2B, 4E, 6C, 8B, 10D, 11D); suture between first and second metasomal tergites absent or indistinct (Figs 2B, 4E, 6C, 8B, 10D, 11D).. ................................................................................................... 2

- Metasomal tergites 1–3 often sculptured, sometimes third metasomal tergite smooth (in Paradelius) (Figs 12G, 14B, 16B, 18A); suture between first and second metasomal tergites distinct (except Sculptomyriola), often crenulate (Figs 12G, 14B, 16B, 18A)........................................................................................... 4

2. Occipital carina absent ventrally, not fused with hypostomal carina (Figs 1A & E); propodeum not divided into anterior and posterior parts, with distinct midlongitudinal carina posteriorly, and lateral vertical carinae, with marginated smooth areas (Fig. 1F); fore wing vein r absent (Fig. 2C); fore wing vein cu-a postfurcal (Fig. 2C)................................................................................................. Carinadelius Ranjith & van Achterberg, gen. nov.

- Occipital carina present ventrally, fused with hypostomal carina (Figs 4A, 6A, 8A, 10A, 14A, 16A); propodeum either divided or not divided into anterior and posterior parts, without midlongitudinal carina posteriorly, often without vertical lateral carina and marginated areas of propodeum often sculptured (Figs 1F, 4D & E, 6C, 8B, 10C & D, 11D); fore wing vein r absent or present (Figs 4F, 6D, 7A, 10E, 11A); fore wing vein cu-a antefurcal or postfurcal (Figs 4F, 6D, 7A, 10E, 11A)........... 3

3. Eyes glabrous or short setose (Figs 9C, 11K); fore wing vein 1-R1 completely absent (Figs 7A, 9A, 11A); fore wing vein 1-SR often present and narrow (Figs 7A, 9A, 11A); length of malar space smaller than basal width of mandible (Figs 7B, 9C, 11K); clypeus more than 0.75 × as wide as face (Figs 7B, 9C, 11K)........................... Myriola Shestakov re-instated

- Eyes long setose (Figs 3D, 5E); fore wing vein 1-R1 present (Figs 3A, 4F, 6D); fore wing vein 1-SR often absent, if present wide (Figs 3A, 4F, 6D); length of malar space larger than basal width of mandible (Figs 3D, 5B); clypeus less than 0.75 × as wide as face (Figs 3D, 5B).................................................................. Adelius Haliday

4. Prepectal carina absent (16D); third metasomal tergite entirely sculptured (Figs 15B, 16B); fore wing vein 1SR+M often connected with 1-M (Fig. 16C); propodeum distinctly divided into anterior and posterior part, with distinct submedian transverse carina (Figs 16B & D); male genitalia with indistinctly developed digitus; apical sternite of male narrow, sparsely setose apically; antenna with 20 antennomeres.............................................. Sculptomyriola Belokobylskij

- Prepectal carina present (Fig. 12H); third metasomal tergite smooth, sometimes basally sculptured (Figs 12G, 14B, 17F, 18A); fore wing vein 1SR+M connected with parastigma (Figs 12A, 13A, 14C, 18C); propodeum either divided or not divided into anterior and posterior part, with distinct submedian carina (Figs 12B, 17F, 18A); male genitalia with distinctly developed digitus (unknown in Sinadelius); apical sternite of male broad, setose apically (unknown in Sinadelius); antenna with 20–22 antennomeres........................................................................................ 5

5. Second metasomal suture absent (Figs 17F, 18A); second metasomal tergite sculptured basally, smooth apically (Figs 17F, 18A); third metasomal tergite smooth (Figs 17F, 18A); propodeum mostly smooth with distinct medial transverse carina (Figs 17F, 18A); antenna with 22 antennomeres................................................. Sinadelius He & Chen

- Second metasomal suture present (Fig. 12G); second metasomal tergite sculptured entirely (Fig. 12G); third metasomal tergite sculptured at least basally (Fig. 12G); propodeum mostly sculptured, often without medial transverse carina (Figs 12B, 14B); antenna with 20 antennomeres.......................................................... Paradelius de Saeger