Kwik-Key to Common Families of Hymenoptera
Answer for your specimen:
If you have reached this part of the key, your specimen probably belongs to the superfamily Evanoidea, characterized by having the metasoma (abdomen) attached to the propodeum (thorax) very high above the hind coxae.
The three likely families are:
Evaniidae
Ensign wasps
Shiny black and somewhat spider-like. Their small, oval abdomen is attached to the thorax by a slender petiole and often moved up and down like a signal flag (hence the common name). Larvae are parasites of cockroach egg cases.
Gasteruptiidae
Carrot wasps
Abdomen is very long and slender. Hind tibia expanded. Ovipositor very long. Head is set on a “neck”, differentiating from ichneumons. Larvae are predators of other Hymenoptera that nest in twigs and in wood. Adults feed at flowers, especially those of the carrot family, Apiaceae.