Automeris io (the "Io Moth") is a widespread North American member of the wild silk moth family, Saturniidae. Peale collected and reared larvae of this common moth and apparently he mistakenly believed it to be a member of the "tent caterpillar" family Lasiocampidae. The incorrect generic name Lasiocampa appears on the plate depicting Automeris io that was published as part of Peale's prospectus for Lepidoptera Americana (1833). The Academy of Natural Sciences Library holds Fifteen plates of Peale's from his prospectus for Lepidoptera Americana.

Lepidoptera Americana Plate 6

The Io Moth is one of only a few North American silk moths whose larvae posess stinging spines. When an animal or person brushes against the caterpillar, these spines (actually hollow setae) fracture releasing venom produced in glands along the length of the caterpillars body. The result is a painful stinging sensation often followed by swelling. When young, the caterpillars are gregarious. They feed on a wide variety trees and shrubs and occasionally attack cultivated crops such as corn. In the text accompanying the plate reproduced here from Lepidoptera Americana, Peale noted varous willows (Salix spp.), dogwood (Cornus spp.) and sassafras (Sassafras albidum) as larval hosts. He also cited specimens in the "Philadelphia Museum" which may correspond to specimens surviving in the extant Peale Collection.

Automeris io specimens in the Peale Collection

Box 21, Specimen 25
Box 21, Specimen 26
Box 21, Specimen 27
Box 21, Specimen 28
Box 21, Specimen 29
Box 21, Specimen 30
Box 75, Specimen 4
Box 75, Specimen 5
Box 75, Specimen 6
Box 75, Specimen 7
Box 75, Specimen 8
Box 75, Specimen 9
Box 75, Specimen 10
Box 75, Specimen 11
Box 75, Specimen 12