The Atlas Moth (Attacus atlas), a Southeast Asian saturniid moth, is among the largest lepidopterans in the world, with a maximum recorded wing span of 262 mm. Although this is not the largest lepidopteran wing span known (that record goes to the noctuid moth Thysania agrippina), it is apparently the second largest. In terms of wing surface area, the Atlas Moth (or possibly one of its also very large close relatives) is likely the largest lepidopteran. (Kons 1998 and references therein)
The large, striking Atlas Moth larvae (caterpillars) are well defended. They are able to spray a strong-smellling defensive secretion that apparently is used against vertebrate and ant predators. This can be sprayed up to 50 cm either as a droplet or fine stream. (Deml and Dettner 1994 and references therein)
Atlas Moth larvae produce silk with mechanical properties similar to silk from the domesticated silkworm (Bombyx mori), although the two silks have different amino acid compositions (Pérez-Rigueiro et al. 2001).