The Diapriidae

Petiole about two and a half times as long as its middle width; scape very long, fully equal to the height of the head as seen from the side; radial cell completely closed at apex. (Elongate, very narrowly built species with the scape entirely yellowish)

Petiole at most one and a half times as long as its middle width; scape short, obviously not equal to the height of the head; radial cell open or indistinctly closed at apex