Io Moth Caterpillar (Automeris io): This beautiful caterpillar was recently found along the Missouri River near Fort Benton, MT. Unfortunately, the photographer discovered it from the painful “sting” it can deliver from its urticating spines. The Io Moth is typically found in the eastern two-thirds of North America, but as this report suggests, they have slowly made their way into MT. Their numbers have been significantly decreasing over the past few decades. The adult moths are distinctive because of their prominent eyespots on the hind wings. The males have bright yellow forewings, body, and legs, while females have reddish brown forewings, body, and legs. Photo of caterpillar taken on 8/5/17 near Fort Benton, MT.