Monarch butterfly (Danaus plexippus)
One of the best-known butterfly species, the beautiful monarch butterfly (Danaus plexippus) is renowned for its spectacular, long-distance annual migrations. The adult monarch butterfly is brightly coloured, with orange upperwings, interlaced with black veins and surrounded by a wide, black border marked with numerous white spots. While the striking colouration of the upperwings serves as a visual warning to predators that this species is poisonous, the undersurface of the wings is duller orange, and helps to camouflage this species against tree bark and other substrates when at rest. Male and female monarch butterflies can be readily distinguished by the fact that the adult male is slightly larger than the female and has a black spot on each hindwing.
Like the adult, the fully-grown monarch butterfly caterpillar is also highly distinctive, possessing bold, yellow, black and white bands over the entire five centimetre-long body, with a pair of long black filaments near the head and a pair of shorter filaments towards the rear. During metamorphosis the caterpillar forms a lime-green chrysalis, marked with gold spots and a black, horizontal band edged with gold.