Io Moth Caterpillar
Don't let this caterpillar get under your skin. The larval stage of the io moth is capable of inflicting very painful stings.
The larval stage of the io moth ranks near the top of any list of problematic stinging caterpillars. The spines that cover the caterpillar are connected to poison glands. As with any stinging caterpillar, contact with the spines can be very painful — the sensation is similar to a bad bee sting; the pain can often last several hours.
The caterpillar feeds on many trees and shrubs, including willow, maple, elm, oak, holly, boxelder, aspen, locust, cherry, pear and sassafras.
The adult has a wingspan of two to three inches. The female is mostly dark brownish-purple and is larger than the male, which has yellow forewings. Both sexes have prominent eyespots.