Zygaena erythrus, common name sluggish burnet, is a species of moth in the family Zygaenidae.

[1][3] It prefers dry and rocky areas with sparse vegetation and limestone substrate, but it is also present in heathlands, in nutrient-poor grasslands and in broad verges in oak forests with the host plant Eryngium species, from sea level to over 1,500 metres (4,900 ft).

[5] These quite large moths show enlarged and confluent red spots on the forewings, surrounded by black in the distal part.

[6] This species is very similar to Zygaena purpuralis, but it has red scales in the axillary area of the forewings, up to a third of the length.

— As magna [Seitz, [1907] ] (4 a) a very large form from the Abruzzi is sold by Staudinger; the posterior cuneiform spot is strongly widened and distally straight-truncate.— Larva dull greenish yellow, with heavy black dots subdorsally and yellow side-spots (Sapokta); in some districts not distinguishable from the larva of purpuralis.

Pupation occurs within a cocoon usually adherent to the lower surface of the leaves,[6] but also on the ground between lichens, moss and parts of plants.