The genus contains the Atlas moth (Attacus atlas), and Attacus caesar, the second and third largest known moths (in terms of wingspan), though different sources treat one or the other as slightly larger. Both are outclassed by the largest, (in terms of wingspan) moths, Thysania agrippina, also known as the White Witch Moth.[2][3]
Like other saturniid moths, adults lack a fully formed digestive tract and do not feed.
Their life cycle is similar to any other Lepidoptera, with 4 life stages, egg, larvae, pupa, and adult. In the wet season, where host plants are in full flush, they start from eggs laid by the adult female moth, they hatch after about 3 weeks. At the first instar, they are just millimeters long, but quickly grow to 4-5 inches in length by their final instar. Once they reach the 5th and final instar, they start preparing to pupate. During this stage, their fleshy spines shrink some and they start to lose the ability to walk. They spin a silk cocoon around themselves, then molt for the final time. This protects them and keeps a slightly humid microclimate around them at all times, vital to the pupa's survival. This is because they 'overwinter' in the dry season, which would otherwise desiccate the hapless pupa. It molts for the last time, and turns into a large brown pupa. In this state, it will take approximately 1.5-2 months to emerge as a full grown adult. Then it will fly off into the jungle, to find a mate, breed, then die.
Adult moths are predominantly anywhere from cinnabar red to brick red, some even going into deep crimson red. The wingtips of many species mimic the head of a snake, and when threatened the moths will drop to the ground and slowly shake their wings, revealing the "snake head" and hopefully scaring would be predators away. They also have small transparent 'windows' in the middle of their wings.
Their caterpillars are pale green, fleshy, and have large wax covered spines. Younger instars are nearly mint colored, adorned with small blue flecks. As they grow, they become more solidly colored and lose their blue coloring, except on their prolegs and feet.
Media related to Attacus at Wikimedia Commons
Data related to Attacus at Wikispecies
