Tussock Moth (genus Orgyia): Caterpillars can be difficult to properly identify to species as their colors and patterns change as they grow. We’re not convinced, but this might be a Rusty Tussock Moth (Orgyia antiqua). This species is native to Europe but can now be found throughout North America, Europe, and parts of Africa and Asia. Photo by Lisa Winn Cloo 8/29/18 near Hamilton, MT.