Wingspan 30–46 mm. The forewings usually show five crimson to vermilion spots and a black basic colour, with a strong bluish or blue-green reflection. The third spot is smaller than the fourth one and rarely emerged. Head, thorax and abdomen are black and moderately to strongly hairy. The antennae are long and slender and slightly clavate (club shaped) and tapered.
The apex of forewing more pointed and black terminal band on hindwing narrower.
The moth is very similar to Zygaena trifolii and is therefore often confused. Determination by genitalia examination required.

The eggs are pale yellow.

Lenght 19–28 mm. The larvae are bluish green or pale yellow, with long pale hairs (setae) and a few rows of almost rectangular black spots.

The colour of the pupa varies from brown to black. Cocoon detached on the stems of grasses.

The larvae eat until late summer and early winter, and continue to develop in the following year. At the end of May the caterpillars are fully grown. The not fully grown caterpillars overwinter a second time. The caterpillars pupate in an elongated or spindle-shaped yellowish or white cocoon on grasses and other plants.
They are active during the day and visiting different flowers like Scabiosa, Knautia, Cirsium and Centaurea.

The larva lives on different species of Trifolium and Lathyrus.

It prefers dry to mesophilic habitats, open forests, calcareous grassland and chalk downland.