Tiny solitary wasps 0.5-1.5mm long. Under high magnification, the compound eyes are usually covered in short, dense setae (fine hairs). They possess a distinct ridge (the occipital carina) at the back of the head, but they lack a hyperoccipital carina (a second ridge across the top), which helps distinguish them from some related genera like Trissolcus. Female antennae are clavate (club-like at the end), males moniliform (bead-like). The mesosoma (thorax) is often strongly convex or "humpbacked," with the head carried relatively low. The wings have reduced venation with the postmarginal vein typically longer than the stigmal vein. The edges of the wings, especially the hind wings, often have a fringe of long hairs (cilia).

This genus is species-rich with possibly more than 1,000 species worldwide and up to 50 in the UK. The taxonomy of the genus is currently undergoing re-evaluation due to DNA barcoding. Identifying specimens to species level is very difficult and not helped by taxonomic uncertainty.

Unless identified by a recognised expert, details of how the specimen was identified must be provided. 

Unknown, under recorded due to identification difficulty. 

Unknown.