Asymmetric mandibles, right mandible has 4 acute teeth, left mandible has only 3 teeth. The antennae are inserted relatively low on the face (near the lower margin of the eyes). The anterior margin of the clypeus is shallowly notched in the centre, without a large single median tooth.

At least 34 UK species, very difficult to identify.

Unless identified by a recognized expert, explain how the specimen was identified and submit photos of key features. 

All year. 

Mesopolobus species have been reared from hosts spanning five different insect orders: Hymenoptera, Diptera, Coleoptera, Lepidoptera, and Hemiptera.

Fertilized adult females find shelter during the winter months inside dense, evergreen conifer foliage. They emerge early in the spring, synchronized with the lifecycle of host populations.

Widespread.

Unknown.

Graham, MWR de V. (1969) The pteromalidae of north-western Europe (Hymenoptera: Chalcidoidea). Bull. Br. Mus. nat. Hist. (Ent.) Suppl. 16.