The adult is a strikingly marked and elongate bug reaching a length of 6 to 8 mm. The largely black pronotum is strongly narrowed at the front, forming a distinct collar which is marked with yellow or white. The antennae are red tipped.

This species can be identified with care but there are similar species that it could be confused with.

Usually recorded on oak.

Adults are found mainly from late May to July.

A largely predatory bug, feeding on other small animals such as aphids and bark flies, as well as unopened oak catkins and young acorns. This species overwinters as eggs, which hatch in spring producing pale whitish blue-green larvae.

Fairly frequent and widespread in Britain.

Status in Leicestershire and Rutland not known.