Cethosia biblis is medium-sized butterfly, with a wingspan reaching about 8–9 centimetres (3.1–3.5 in). In this species the sexes are dimorphic. In males the dorsal sides of the wings are bright orange red, framed by a black outline with white spots. The undersides range from bright red to pale brown, interlaced by black and white. This astonishing pattern helps to disguise the shape of the butterfly, while the intense colour of the dorsal sides of the wings is a warning to predators that the red lacewing has a bad taste, deriving from the poisonous host plants of the caterpillars. The dorsal sides of the wings of the females are greyish-brownish with black spots and white bands and spots on the black margins.
Caterpillars have several reddish, black and white stripes, a black head and long black spikes that contain poison. In fact they mainly feed on poisonous climbing plants, mainly Passiflora species (P. cochinchinensis, P. moluccana, etc.).