3 to 4mm. Variable, usually dark blue or dark green with a brassy metallic lustre. Elliptical and convex with a transverse pronotum that strongly narrows at the front. The elytral punctures are spaced out, roughly 4x the size of each puncture. P. tumidulus is distinguished from the other three Phaedon species by the pronotal disc being sparcely and very finely punctured.

Woodland, parkland, wasteland and domestic gardens where umbellifers are present.

Spring and summer.

Feeds on plants in the Apiaceae family.

Common throughout England, Wales and southern Scotland with only scattered records north of Edinburgh-Glasgow.

Fairly frequent in Leicestershire and Rutland.