Genus Episyron Schiødte, 1837

Episyron Schiødte, 1837: 341 . Type species: Sphex rufipes Linnaeus, 1758, by monotypy.

Diagnosis. Ground colour black; dense brown, grey, or bluish white lanceolate scales or setae largely covering pronotum, scutellum, metanotum, mesopleura, metapleura, propodeum, dorsum of hind coxa and T1; clypeus large, upper margin somewhat sinuous; mandibles bidentate in female, unidentate in male; malar space, if any, shorter than half of pedicel; apex of apical flagellomere obliquely truncated with smooth area; metapostnotum strongly developed, constricted on the median line and just in front of spiracles, posterior margin arcuately expanded between the constrictions; posterolateral portion of propodeum smooth; protarsus with comb, tarsomere 2 with 1–2 midspines; all claws in both sexes bifid; fore wing with three SMC; anal lobe of hind wing fairly large, about half the length of submedian cell; metasoma stouter in female than male; female pygidium without bristles (Evans 1949; Loktionov & Lelej 2015; Kim 2022).

Biology. Members are found to be ectoparasitoids of the spider family Araneidae (Wasbauer & Kimsey 1985) .

Distribution. All major zoogeographic regions (Kim 2022).

Key to species of Episyron Schiødte occurring in India

( E. zebra (Cameron, 1891) excluded due to lack of sufficient details in description).

1. T3 almost entirely reddish brown or yellow................................................................. 2

- T3 either entirely black or black with yellow markings........................................................ 3

2. Clypeus very convex, its anterior margin boldly arcuate and turned downwards; propodeum gradually sloping to apex; metasoma black with basal three segments and base of fourth ferruginous red....................... E. fenestratum (Smith, 1855)

- Clypeus moderately convex, transversally rectangular; propodeum with a steep slope to apex; metasoma black with third and fourth segments yellow.......................................................... E. infestum (Bingham, 1896)

3. Primary colour of hind tibia red.......................................................................... 4

- Primary colour of hind tibia black........................................................................ 5

4. Propodeum gradually sloping to apex; hind tibia dorsally with a yellowish white spot....... E. vagabundum (Smith, 1858)

- Propodeum with a steep slope to apex (Fig. 34); hind tibia dorsally without any coloured spot (Fig. 39)......................................................................... E. rufotibius Anju, Girish Kumar & Thejass, sp. nov.

5. Clypeus entirely black (Fig. 19); hind tibia black without any marking (Fig. 27); tibial spurs black (Fig. 27); numerous long black setae on T6, almost uniformly distributed (Fig. 25)...... E. nigrocalcarius Anju, Girish Kumar & Thejass, sp. nov.

- Clypeus black with pale yellow markings; hind tibia black with pale yellow fascia in dorsal face basally; tibial spurs pale yellow; long black setae on T6 moderate, concentrated laterally................................................. 6

6. Head not wider than mesosoma; SMC3 distinctly smaller than SMC2; crossvein 2m-cu of forewing nearly straight....................................................................................... E. arrogans (Smith, 1873)

- Head wider than mesosoma; SMC2 and SMC3 almost equal in size (Fig. 12); crossvein 2m-cu distinctly curved basally (Fig. 12).................................................... E. keralaensis Anju, Girish Kumar & Thejass, sp. nov.