It differs in its outward appearance and way of life from other "grass bugs" in the Stenodemini,[3] being predatory and an effective ant mimic.

[3] The appearance of a typical hymenopteran "waist" is created by the paler coloration of the front of the abdomen and the back of the thorax, contrasting with the rest of the body which is mainly black, effectively camouflaging the bug's thick waist.

[3] The generic name is from Ancient Greek: Μύρμηξ, Múrmēx, ant, and κόρῐς, kóris, bug.

The bug lives on dry and warm to moderately damp, grassy open habitats.

[6] It is described as a "not common" inhabitant of dry heathland in Britain, where it is confined to the far south of England in an area bounded by Exeter, Bristol, Oxford, Luton and Eastbourne.