The Large or Cabbage White (Pieris brassicae) is an exception in the bright world of butterflies.
Most butterflies have brightly-coloured wings - wing colour and pattern play a major role in courtship. Night-flying or crepuscular moths usually have plain colours – black, brown, grey or white. Females attract males by releasing a chemical signal. Additionally their wings may have swirling or linear patterns which serve as camouflage when they are resting during the day. Exceptions are the day-flying moths which have bright colours, especially if they are poisonous. Moths have a frenulum – a minute hook or bristle – linking fore and hind wings. Butterflies lack this feature – usually. There is an Australian Skipper which has this.
The bodies of butterflies are slim while moths have sturdier often hairy bodies. Moths tend to look quite downy because the scales on their wings are larger, perhaps because they need to conserve heat in the cool of the night. Butterfly scales are smaller and they can utilise solar radiation.
The Dingy Skipper (Eryynis tages) looks quite like a moth with its thick body and habit of resting with wings outspread.