3.5 to 4.7 mm. Deep metallic. Pronotal disc with both fine and coarse punctures. Distinctly swollen 'shoulders' (humeral calli). Antennae entirely dark and widely spaced.

• 3.3-4.2mm
• Dark metallic blue
• Antennae black
• Legs dark brown to black
• Pronotal disc punctures a mix of fine and coarse and not finer on the lateral punctures
• Pronotal sides smooth, without microsculpture
• Apical abdominal sternite with a yellow band
• Humeral calli distinct

Adults are found on a variety of water plants, though larvae have only been found on brooklime.

Common and widespread throughout Britain.

Fairly frequent in Leicestershire and Rutland.