Length: 5 - 8mm.  Background colour: (1) ‘succinea’: yellow/orange/red; (2) ‘spectabilis’ and (3) ‘conspicua’: black.  Pattern colour: (1) with 0-21 black spots; (2) with four red/orange spots/patches; (3) with two red/orange spots/patches.  Number of spots: 0-21 (16).  Spot fusions: common in ‘succinea’ form.  Melanic (black) forms: common (‘spectabilis’ and ‘conspicua’).  Pronotum: white or cream with up to 5 spots, or fused lateral spots forming 2 curved lines, M-shaped mark or solid trapezoid.  Leg colour: brown.  Other features: many specimens have a slight keel along the posterior margin of the dorsal surface; extremely variable in colour and pattern.

Fourth-instar larva: black, with thick dorsal spines coming from each tubercle, each branching at the top into three prongs; bright orange upside-down L-shaped marking on each side, made from middle tubercles of abdominal segments one to five and inner tubercles of abdominal segment one; two pairs of orange dots on dorsal surface, made from inner tubercles of abdominal segments four and five.  Pupa: orange, with pairs of black squarish markings running down the second thoracic segment and abdominal segments two to six; remains of shed spiky larval skin visible at base of pupa.