The Distribution of Three Broadly Sympatric Species of Symmerista Moths (Lepidoptera: Notodontidae) in the Great Lakes and Midwest Regions of the United States.

All three superficially inseparable species of Symmerista known to occur in eastern North America are sympatric in, and reach their western limit of distribution in, the southern Great Lakes and Midwest Regions of the United States. In this region two of the species also reach their southern limit of distribution (S. canicosta reaches its southwestern limit in North Dakota, South Dakota, Missouri, Kentucky, and North Carolina; S. leucitys reaches its southwestern limit in North Dakota, Missouri and Kentucky). The third species (S. albifrons) reaches its northwestern limit in Michigan and Wisconsin. All three species are here documented from well beyond their previously reported ranges, and distribution maps are provided for them. Diagnostic male abdominal structures are figured. Larvae of Symmerista are frequently reported as defoliators of oak (Quercus), maple (Acer), and other hardwoods.