In Latin, "gibbos" or "gibbus" refers to a protuberence or hump. "Osa" suggests "rich in" or "abounding in". Since this rich hump is lacking in the caterpillar, I assume it to be a refererence to that thoractic tuft so prominently displayed on this adult moth.
The "White-dotted" part in its common name, though, requires no speculation.
