Length 1.5-2mm. Typically dark, metallic greenish-black sheen across the head and thorax. The petiole ("waist") is longer than broad and obvious from above. Antennae elbowed (geniculate) antennae, with 13 segments including 2 ring segments. Genae bordered by a strong carina which extends some distance up the temples. Frenal line (furrow) of scutellum strongly impressed. Head in dorsal view with temples straight, only moderately convergent, forming an angle with the occipital edge of the head; speculum of forewing well-defined; femora mainly fuscous to black, tibiae at least slightly brownish, usually mainly fuscous to almost wholly black.

The other UK species, A. suspensus - temples curved and rather strongly convergent, not angulate posteriorly; speculum of fore wing indistinct or absent; legs, not counting the coxae, testaceous with the femora sometimes more or less infuscate proximally, rarely the tibiae with a dark ring.

Unless identified by a recognised expert, explain how the specimen was identifed and indlude photos of key ID features. 

All year. 

Endoparasitoid of aphids.

Common and widespread. 

Unknown.