Description: Wingspan 50-78mm. A colourful, distinctive species. Both sexes similar in appearance. Forewings are dark chocolate brown with ochreous white streaks and patches, which are variable in size and shape. Hindwings are orange-red with a series of deep blue-centred, black spots. Abdomen is red with black bars on the dorsal side. The scarlet hindwings are a distinctive feature of this species, which it readily displays when disturbed. Some interesting aberrations, in which most of the chocolate brown markings on the forewings have been replaced with white, have been recorded from the coastal locality of Killard Point NNR, Down. From late June until the latter half of August.

World Distribution: Across the northern Palaearctic region.

Irish Distribution: Widespread and commonly encountered throughout all counties.

Ecology: Found in a wide variety of habitats including woodland, bogs, coastal heaths and dunes. The adults are seldom found by day but appear frequently at light. Many of the records are of larvae, which are commonly referred to as 'woolly bears' or 'granny greybeards'. These are often seen by non-naturalists, wandering across paths and roads in search of a suitable pupation site. The distinctive larvae feed from September until June of the following year on a wide variety of wild and garden plants. It overwinters as a larva.

Key Identification Features:

• Difficult to confuse with any other species
• Brown and white markings on forewings
• Red hindwings with dark blue spots

Distribution Map from NBN: Arctia caja at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Arctia caja at iNaturalist World Species Observations database.