The tribe Acraeini of subfamily Heliconiinae, family Nymphalidae, includes numerous brightly coloured butterfly species. Many feature patches of red colouring, though few are entirely red. The genus Rubraea contains some of the most vividly red Acraeini. There are 48 species in Africa, 6 in South Africa. Some have a mix of orange and red, while others possess extensive clear (or hyaline) wing areas. The males exhibit the brightest colours, while females may be red but also tend to be brown or bronze with extensive black areas. Many females have white forewing tip patches that contrast with their ground colours.

The males of Rubraea petraea, commonly known as the Blood-red Acraea, display probably the deepest red within the genus. They are not completely red; unlike the red gliders (genus Cymothoë) of central Africa, they have black spots on their wings. When viewed against the green background of a forest glade, the red coloration is prominent despite the black spots.

Blood red is often described as ranging from crimson to brownish red depending on the level of oxygen in the blood. Males of Rubraea petraea often exhibit a more bluish shade of red that is probably closer to carmine than crimson. Fire-engine red, or Ferrari red, is perhaps a better description of their appearance. It’s a matter of opinion – look at some of the photos for examples. Males may have a whitish suffusion along the anal margin of the hindwings.

Female Blood-red Acraeas vary in hue from brick-red to brown to pale bronze. They have white patches at the apex of their forewings. These are usually white but may be suffused with pink.

The redness of Acraeini is affected by the age of the butterfly, with older ones fading to a paler, less saturated red or even brick-red. Dead, pinned specimens in collections soon fade to brownish red, even if stored in the dark. It may be that the red pigment oxidises and as it does so it may lose its vibrance.

The underside of both sexes has a ground colour of pale pink to whitish grey in the discal area with a mosaic of dark pink marks and black spots towards the base. The wing veins are picked out in black; between the veins are a series of orange to pink postdiscal marks. The hindwing underside has a black submarginal line with white marginal lunules.

Males form territories in clearings in the bush, periodically taking off to float over the canopy, settling on leaves or twigs with wings held open. Females tend to be located near their host plants but also patrol the woodlands. When a male spots a female, he may drop onto her from a height and forcibly mate with her. Both sexes exhibit a preference for flower nectar.