Slug moth caterpillar

It looked transparent on the leaf, we had to look very carefully to find it. The Limacodidae or Euclidae are a family of moths and they are often called slug moths because their caterpillars bear a distinct resemblance to slugs. They are also called cup moths because of the shape of their cocoons. The larvae are often liberally covered in protective stinging hairs, and are mostly tropical, but occur worldwide, with about 1000 described species and probably many more as yet undescribed species.