The elytra and pronotum are covered in fine scales of different colours, creating an irregular pattern of white, brownish and yellowish patches on these features.

The white scales are focussed along the lateral margins of the pronotum and on the elytra, where they form three bright, wavy transverse bands.

[2] The larval form of A. verbasci, commonly known as 'woolly bears' (a name shared with the larvae of Arctia caja and many other moths of the subfamily Arctiinae), measures up to 4–5 millimetres (0.16–0.20 in) in length.

These hairs are organised into alternating, transverse groups of light and dark-brown patches: the larva appears covered in brown stripes.

During this period, mating occurs and the eggs are laid, either close to the human environs or in bird nests, tree hollows and similar, dry places where larvae can find their food.

[8] Larvae feed on keratin and chitin of natural fibers (dead insects, animal hair and feathers) throughout their development, eventually experiencing a dormancy period (also known as diapause) prior to pupation into the adult stage.

By comparison, the closely related beetle species Anthrenus flavipes – which has slightly longer hairs than A. verbasci – uses such a defense more effectively.

[12] In a 1987 survey of British national history museums, at least five noted that A. verbasci was categorised as a major pest for biological collections.

[11] Signs of an infestation include the presence of damaged articles, moulted larval skins in dark areas, and an abundance of adult beetles near windows.

[11] Susceptible people may also find that hairs shed from the larvae cause irritated itchy welts that may be confused with bedbug bites.