Genus Leptochilus de Saussure, 1853

Leptochilus de Saussure, 1853: 233 . Type species: Pterochilus mauritanicus Lepeletier de Saint-Fargeau, 1841, by subsequent designation of Ashmead 1902: 209 (as “ Pterochilus mauritianus, Lepel. ”); Blüthgen 1961: 98–100; Parker 1966: 151–229; Giordani Soika 1970: 63–77; van der Vecht & Fischer 1972: 42–53; Kurzenko 1982: 100; Gusenleitner 1977: 163–178; 1985: 81–101; 1993: 745–769; 1995a: 169–181; 1995b: 768–771; 2013a: 43–54; Buck et al. 2008: 216–221; Carpenter et al. 2010: 158–159; Kumar & Carpenter 2015: 7786–7790; Antropov & Fateryga 2017: 185.

Remarks. Due to the vast literature on the genus Leptochilus, only the most important references relevant to the present study are cited above.

It is not easy to complete a definitive diagnosis of the genus due to its high variability. Usually, its representatives could be recognized by the following characters: head shorter or not much longer than its wide; proboscis not reaches mid coxae; thorax not much longer than its wide; pronotal foveae absent; pronotal carina present; tegula protruding posteriorly; second submarginal cell of forewing with obtuse basal angle; metanotum sharply edged posteriorly; propodeal valvula bilamellate, submarginal carina projecting as rounded lobe above valvula; tergum 1 hardly petiolate, without transverse carina, depressed subapically (Parker 1966; Kurzenko 1982; Carpenter & Garcete-Barrett 2002; Buck et al. 2008; Gusenleitner 2013a; Tan et al. 2018). Old World species also have a peculiar apical lamella on tergum 2; this lamella has a basal row of small to large punctures. Representatives of the genus are usually very small wasps (except subgenera Leptochilus s. str. and Euleptochilus, which comprise rather mediumsized ones).

Subgenera included. Euleptochilus Blüthgen in Berland, 1943 (16 species); Leptochilus s. str. (1 species); Lionotulus Blüthgen, 1938 (90 species); Neoleptochilus Blüthgen, 1961 (27 species); Sarochilus Gusenleitner, 1970 (11 species); Zendalia Robertson, 1928 (55 species).