Dryas iulia (often incorrectly spelled julia) is also known as the Julia butterfly, Julia heliconian, the flame, or flambeau. It is the sole member of the genus Dryas, native from Brazil to the southern United States. There are more than 15 described subspecies.
Approximately 80-90 mm across, its elongated wings are primarily orange with black markings. Males are slightly brighter orange than females. The Julia butterfly is a fast flier, living in open, sunny clearings, paths, and margins of forests and woodlands. The adult feeds on nectar; the caterpillar feeds on leaves of vines.
Males and females eat different things based on their reproductive needs. Males engage in mud-puddling behavior (essentially, drinking from water puddled on the ground) to gain minerals for their spermatophores. (They also gain minerals from irritating the eyes of reptiles like caiman and turtles!) Females eat nectar, as well as pollen from flowers to gain nutrients needed for egg production.
They have a complex social mating dance which appears to be led by the female. The eggs are light yellow, turning darker before hatching. The caterpillar are orange with large black spikes, which can produce a rash in humans if they touch the caterpillar. The larval stage emits noxious chemicals on the spikes due to trace amounts of cyanide in their host plants, and are therefore also mildly unpalatable to birds.