What is a distinctive characteristic of 'Saturniidae' caterpillars?

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. They are also known as 'Wild Silk Moths'.

'Saturniid' caterpillars are medium to very large in size, and this family includes the largest moths in North America. Adults have relatively small heads and densely hairy bodies. Larvae are usually very fleshy, with clumps of raised bristles.

Most 'saturniid' larvae feed on the foliage of trees and shrubs. A few, such as 'Automeris louisiana', 'A. patagonensis', and 'Hemileuca oliviae', feed on grasses.