The colors of the adult are always primarily yellow with red, brown, and purple blotches but can vary distinctly on this.

[3] Imperial moths (their many regional morphs, subspecies, and sibling species) range from Argentina to Canada and from the Rocky Mountains to the Atlantic Coast.

[3] The true northern limits of the nominate's range are unknown because of possible confusion with subspecies E. i. pini in existing records.

Subspecies E. i. pini occurs in coniferous and transition zone woodlands at the northern edges of the New England and Great Lakes States and northward into Canada.

[6] Reasons for the decline have been proposed to be the use of pesticide, insecticides, and herbicides in commercial farming, metal halide street lamps, and the introduction of parasitoids in the attempt to control the spongy moth population.

[4] A population on Martha's Vineyard, Massachusetts, has been the subject of scientific and local political activity, especially concerning the preservation of the sensitive frost-bottom oak/pine habitat.

[6] E. imperialis is certainly a common species of middle-Atlantic states, Appalachia, the Ohio Valley, and Deep South regions, and is associated with forest, rural and suburban habitats.

It is possible that to the north, E. imperialis requires specific habitat and that the increasing fragmentation of niches such as coastal or montane pine barrens is a factor.

Abdominal segments are moveable but are unable to telescope because of flanges on the anterior margins of the abdomen.

Sexual dimorphism is present in the adult stages of this species: Male Female Larvae feed on a variety of host plants from Coniferous and deciduous trees to shrubs.

[9] On Martha's Vineyard, E. i. imperialis feeds almost exclusively on pitch pine (Pinus rigida).