The Diapriidae

Couplet 5.

History
   [1] Fourth antennal segment never modified; a sexual mod...
     [2] Mandibles long, sickle-shaped, widely crossing at ti...
       [3] Marginalis never as short as this, always obvious
         [4] Marginalis much shorter, never as long as ...

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postscutellum, in profile, with a triangular projection

Paroxylabis Kieffer

Post scutellum, in profile, without such a projection

Aclista Foerster