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. There were approximately 28 VC55 records for this species up to March 2015.