This is quite a distinctive red beetle with red wing-cases, thorax and head, and black legs. Similar to Pyrochroa coccinea which is larger and has a black head. Length 10 to 18mm.
The larvae predate on other insects.
They are seen May to July, in woodland and hedgerows. Common and widespread in the south of England and in Wales, becoming scarce further north and absent in Scotland.
Photograph of Cardinal Beetle (Pyrochroa serraticornis) taken May 2014, local woodland margin, Staffordshire. © Pete Hillman 2014. Camera used Nikon D3200, with Sigma 105mm macro lens.