Tribe Adeliini Viereck, 1918

Diagnosis. Head transverse, sculptured (Figs 1B, 3D, 5B, 7B, 9C, 11K, 12I, 13B, 15C, 17B); ocelli small; frons flat or concave medially, with or without midlongitudinal groove (Figs 1C, 4C, 5C, 7C, 9D, 11C, 12C, 13C, 15D, 17C); eyes setose (Figs 1B, 3D, 5B, 7B, 12I, 13B, 15C, 17B) or glabrous (Figs 9C, 11K); malar suture complete and deep (Figs 1E, 3D, 5D & E, 7D, 10B & E, 11I & K, 15E); occipital carina often complete, joining hypostomal carina ventrally (Figs 4A, 6A, 8A, 10A, 14A, 16A), rarely absent ventrally (Figs 1A & E) (in Carinadelius gen. nov.) without joining hypostomal carina; palps short and thick, maxillary palp often 5-segmented (Figs 1E, 4A, 13E) rarely 3-segmented (Fig. 12F) (in Paradelius), labial palp 3-segmented; antenna more or less thickened, 20–22 antennomeres; scape rather long, wide; pedicel short; first flagellomere longer than second; subapical flagellomeres of female quadrate in several species (Figs 2A, 5A, 7C); tentorial pits deep (Figs 1B, 3D, 5B, 7B, 9C, 11K, 12I, 13B, 15C, 17B); clypeus smooth or sculptured (Figs 1B, 3D, 5B, 7B, 9C, 11K, 12I, 13B, 15C, 17B); labrum concealed by clypeus (Figs 1B, 3D, 5B, 7B, 9C, 11K, 12I, 13B, 15C, 17B); mesosoma often dorso-ventrally flattened (Figs 1E, 4B, 6B, 7F, 10B, 11I, 13E, 15E, 17E); propleuron short, crenulate posteriorly (Figs 1E, 4B, 6B, 7F, 10B, 11I, 13E, 15E, 17E); propleural lobe distinct or indistinct (Figs 1E, 4B, 6B, 7F, 10B, 11I, 13E, 15E, 17E); mesoscutum smooth to sculptured (Figs 1D, 4C, 5F, 7E, 9F, 11L, 12B, 13D, 15D, 17C); notauli absent (Figs 1D, 4C, 5F, 7E, 9F, 11L, 12B, 13D, 15D, 17C); prepectal carina often absent (Figs 1E, 4B, 6B, 7F, 10B, 11I, 13E, 15E), rarely present (Fig. 12H, 17E) (in Sinadelius and Paradelius); postpectal carina absent (Fig. 9E); scutellar sulcus narrow, crenulated (Figs 1D, 4C, 5F, 7E, 9F, 11L, 12B, 13D, 15D, 17C); mesopleuron convex, smooth or sculptured (Figs 1E, 4B, 6B, 7F, 10B, 11I, 12H, 13E, 15E, 17E); precoxal sulcus smooth or crenulate entirely (Figs 1E, 4B, 6B, 7F, 10B, 11I, 12H, 13E, 15E, 17E); metapleuron smooth (Figs 1E, 7F, 10B, 13E, 17E) or rugose (Figs 4B, 6B, 15E); propodeum smooth or sculptured, often areolate, either divided into distinct anterior and posterior part or not (Figs 1F, 4D & E, 6C, 8B, 10C & D, 11D, 12B, 13F, 14B, 16B, 17F, 18A), rarely with distinct midlongitudinal carina and vertical lateral carina posteriorly (Fig. 1F) (in Carinadelius gen. nov.); propodeal spiracles round; fore wing hyaline (Figs 7A, 10E, 11A, 12A, 14C, 18C) or infuscated (Figs 2C, 4F, 6D, 16C); pterostigma wide; vein 1-R1 distinct, long (Figs 2C, 4F, 6D, 10E, 12A, 14C, 18C) to nearly absent (Figs 7A, 9A, 11A); fore wing vein r present (Figs 7A, 9A, 11B & F) or absent (Figs 2C, 4F, 6D, 12A, 14C, 18C); vein r-m absent (Figs 2C, 4F, 6D, 7A, 10E, 11A, 12A, 14C, 16C, 18C); vein SR1 not reaching wing margin; vein 1SR+M either connected with parastigma or 1-M; vein m-cu often postfurcal or interstitial (Figs 2C, 4F, 6D, 7A, 10E, 11A, 12A, 14C, 16C, 18C); vein M+CU straight or distinctly curved (Figs 2C, 4F, 6D, 7A, 10E, 11A, 12A, 14C, 16C, 18C); vein cu-a antefurcal, interstitial or postfurcal (Figs 2C, 4F, 6D, 7A, 10E, 11A, 12A, 14C, 16C, 18C); subdiscal cell open; hind wing with 3 hamuli; basal cell of hind wing narrow; mid coxa with transverse groove dorsally (Figs 4B, 6B, 7F, 16D); hind coxa smooth or rugose; hind femur and tibia flattened; hind tibial spurs long, inner spur approx. 0.5 × as long as basitarsus; hind basitarsus long, 0.8–0.9 × as long as combined length of 2 nd– 5 th tarsomeres; tarsal claws short, simple (Fig. 12E); metasoma smooth or sculptured (Figs 2B, 4E, 6C, 8B, 10D, 11D, 12G, 14B, 16B, 18A), often compressed dorso-ventrally; metasomal tergites 1–3 formed into carapace, smooth or rugose; first and second metasomal suture present (Figs 12G, 14B, 16B, 18A) or absent (Figs 2B, 4E, 6C, 8B, 10D, 11D, 16B); spiracle of metasomal tergites 6–7 absent; ovipositor short, always less than 0.25 × as long as hind tibia.

Genera included. Adelius Haliday, Carinadelius Ranjith & van Achterberg, gen. nov., Myriola Shestakov reinstated, Paradelius de Saeger, Sinadelius He & Chen, and Sculptomyriola Belokobylskij.

Distribution. Cosmopolitan.

Biology. Solitary endoparasitoids of leaf-mining Nepticulidae .

Comments. Shimbori et al. (2019) discussed possible apomorphic and synapomorphic character states between Cheloninae and Adeliini . Apart from the synapomorphic characters, the number of antennomeres is considered as plesiomorphic character to some extent (E.M. Shimbori, personal communication). Within the tribe it has been also found (Kittel & Austin 2014; Kittel et al. 2015, 2016) that the division of the propodeum into distinct anterior and posterior parts (in Adelius, Sinadelius and Sculptomyriola) is a plesiomorphic character as it is absent in other genera (in Carinadelius gen. nov., Myriola and Paradelius). It is suggested that the new genus Carinadelius is probably derived from the genus Adelius .