stinging saddleback caterpillar

Saddleback caterpillar, Gerald J. Lenhard, Louisiana State University,

Updated: April 21, 2021

Key Points

  • Most of the caterpillars that are called stinging caterpillars don't sting like wasps or hornets do. They have hairs or spines that sometimes have a poison gland at the base.
  • When touched, the hairs break off and the poison is injected, causing an inflammation of the skin and a burning sensation that may feel like a bee sting.
  • The reaction can be more severe if the eyes, nose or mouth are affected.
  • Stinging caterpillars are not that commonly found around home and yards. Most feed on native trees and shrubs in wooded areas.

The saddleback caterpillar is not fuzzy, but has a striking green saddlecloth on its back with a purplish brown saddle in the middle. It also has irritating spines.

The puss caterpillar (below) is about 1 inch long, when fully grown, furry, and gray to reddish brown in color. 

stinging puss caterpillar
Photo: Puss caterpillar, Lacy L. Hyche, Auburn University,


The Io moth caterpillar is about 2 1/2 inches long when fully grown. It is bright green with red and white stripes and four rows of short, stinging spines.

io moth caterpillar
Photo: Io Caterpillar Steven Katovitch, USDA Forest Service,

It is not necessary to control any of these caterpillars. They cause minimal damage to trees and shrubs.
Rev. 2020