MICRAGONE MARTINAE
Giant silkworm moths

Adults are characterized by large, lobed wings, heavy bodies covered in hair-like scales, and reduced mouthparts. They lack a frenulum, but the hindwings overlap the forewings to produce the effect of an unbroken wing surface. Saturniids are sometimes brightly colored and often have translucent eyespots or windows on their wings.

Sexual dimorphism varies by species, but males can generally be distinguished by their larger, broader antennae. Most adults possess wingspans between 2.5-15 cm, but some tropical species such as the Atlas moth (Attacus atlas) may have wingspans up to 30 cm. Together with certain Noctuidae, Saturniidae contains the largest Lepidoptera and some of the largest insects alive today.

The majority of saturniid species occur in wooded tropical or subtropical regions, with the greatest diversity in the New World tropics and Mexico, though they are found all over the world. About 12 described species live in Europe, one of which, the emperor moth, occurs in the British Isles, and 68 described species live in North America, 42 of which reside north of Mexico and Southern California.

Saturniid caterpillars are large (50 to 100 mm in the final instar), stout, and cylindrical. Most have tubercules that are often also spiny or hairy. Many are cryptic in coloration, with countershading or disruptive coloration to reduce detection, but some are more colorful.

Some have urticating hairs. A few species have been noted to produce clicking sounds with the larval mandibles when disturbed. Examples: Luna moth (Actias luna) and Polyphemus moth (Antheraea polyphemus). The clicks may serve as aposematic warning signals to a regurgitation defense.