Key to Oriental genera of the tribe Chrysidini

1. Apex of Rs not ditinctly sclerotized, ending at least 3 MOD from anterior wing margin; metanotum with a large cup-like poste- rior projection; apex of T3 with four teeth; head narrow and elongated................................ Stilbum Spinola

- Apex of Rs fully sclerotized and jointed to anterior wing margin, or separated at most 2 MOD; metanotum without or rarely with stout projection; if with metanotal projection, then apex of T3 with five teeth; head transverse, broader than its length.. 2

2. Mesopleuron without scrobal sulcus; apex of T3 various, anyway without four or five teeth..... Primeuchroeus Linsenmaier

- Mesopleuron with distinct horizontal scrobal sulcus.......................................................... 3

3. Discoidal cell incomplete, its outer veins not or not entirely sclerotized........................... Chrysidea Bischoff

- Discoidal cell complete................................................................................. 4

4. Apex of T3 with three or five teeth, sometimes only as angle, and median tooth sometimes almost vanishing in male..... 5

- Apex of T3 with different number of teeth................................................................ 6

5. Apex of T3 with three or five teeth; pronotal carina partially or fully developed; metanotum simple, without projection; flagel- lum subcylindrical, not broadened.–Parasitoid of sphecid or crabronid wasps ( Hymenoptera)....... Trichrysis Lichtenstein

- Apex of T3 with five teeth; pronotal carina absent; metanotum with projection, or as small spine; flagellum usually broad- ened.–Parasitoid of limacodid moths (Lepidoptera)..................................... Praestochrysis Linsenmaier

6. Apex of T3 without teeth; male genitalia modified, with longitudinal crest on aedeagus............. Istiochrysis gen. nov.

- Apex of T3 various; male genitalia unmodified, aedeagus without subsidiary structure................. Chrysis Linnaeus