Adults are usually about 14–18 mm long.
Fine-art photographic collection
Pyrochroa serraticornis
A brilliant red adult produced by a flattened two-year predator living in the paper-thin space under bark.
About this species
Red-headed Cardinal Beetle
Pyrochroa serraticornis(Scopoli, 1763)
Information reviewed15 July 2026
Pyrochroa serraticornis is a cardinal beetle of deciduous woodland. Its flattened larvae live beneath loose bark for at least two years, while the vivid red adults appear for a short period in late spring and summer.
Taxonomy
Animalia · Arthropoda · Insecta · Coleoptera · Pyrochroidae · Pyrochroa
Accepted taxon. · checked 2026-07-15
EuropeBroad range and selected reference localities — not a complete occurrence map.
Europe
Old deciduous woodland, dead trees, logs and bark-rich habitat.
Adults are diurnal and often seen on foliage or flowers in warm weather.
Larvae consume small invertebrates, fungal material and decaying tissue; adults take small insects, pollen and nectar.
Solitary.
What makes this species remarkable?
The larva is extraordinarily flattened, allowing it to patrol a habitat only millimetres deep between bark and dead wood.
Development commonly lasts at least two years under bark, followed by a vivid adult stage that may occupy only a small fraction of the lifespan.
Its cardinal-red colour advertises chemical protection, while the exposed adult shifts from hidden bark life to daylight activity on flowers and leaves.
More photographs
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