Key to the genera related to Trichrysis Lichtenstein

1. Genital capsule with aedeagus bearing longitudinal crest (Figs 1A–1 C); S2 with large black spots connected to lateral margins of sternum (Fig. 3 B). Oriental species..................................................... Istiochrysis gen. nov.

- Genital capsule without subsidiary structure (Figs 1 D–1F); S2 with small black spots distinctly separated from lateral margins of sternum (Figs 3 C, 3D)................................................................................ 2

2. Genital capsule with articulate gonostyle (Fig. 1 F); female scapal basin laterally with fovea or depression.—Nearctic and Neotropical species.............................................................. Caenochrysis Bohart & Kimsey

- Genital capsule with gonocoxa not subdivided and without articulate gonostyle (Figs 1 D, 1E); female scapal basin without depression or fovea................................................................................... 3

3. Fore wing discoidal cell complete; apex of T3 with three teeth, sometimes lateral tooth like simple angle; black spots on S2 usually medially fused, or nearly so, only separated by thin metallic line; gonocoxa of genital capsule with unmodified apex (Fig. 1 D).–Palaearctic and Oriental species)............................................... Trichrysis Lichtenstein

- Fore wing discoidal cell usually incomplete with outer veins faint; apex of T3 usually medially rounded or sinuous between two lateral teeth or angles, rarely with median tooth; black spots on S2 usually separated by 1–2 MOD; gonocoxa of genital capsule with bilobed apex (Fig. 1 E).–Palaearctic, Oriental and Afrotropical species.................. Chrysidea Bischoff