The Harris' Three-spot Moth is typically 0.6 inches to 0.7 inches (17mm to 20mm) in size and has the following descriptors / identifiers: white; big brown dots in corners of wing; black marking; brown furry 'shoulder's; hairy bumps on back; flying.
Territorial Area Map (Visual Reference Guide)
The map below showcases (in blue) the states and territories of North America where the Harris' Three-spot Moth may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.