They are very similar to the glossy shield bug but lighter in colour with dark markings, and a white patch above a black shield-shaped marking at the tip of its wings.
They get their name from the prominent horn-like structures that grow outwards from each shoulder.
The eggs are also similar to the glossy shield bug, being black with small “spines” around the edge, which may be more defined than on the eggs of the glossy shield bug.
The nymphs are dark with a circular red marking on the lower back.
Adult size: 12 mm