Distribution: Ranges from Southern New England and New York west through central Illinois to southern Wyoming and northern Utah and Colorado. Southward it is found on a line from North Carlina through Tennessee to Missouri, and is also seen in Florida. It is also known from North Dakota and Manitoba, perhaps wandering to the more northerly locations. There is probably some confusion in records where this species and S. poecila have not been distinguished.

Seasonality and Size: One brood in most of its range, two in the southern portions. Glaser reports flight dates from 8 May - 7 July in Maryland, but it is found into September in much of its range. In Florida its season is from February into April. Wingspan 68-95mm.

Larva and Host Plants: The larva has been found on a wide variety of food plants including larch, apple, sweet gale, blueberries, huckleberries, white spruce, sweetfern, rose,spirea and other woody species. Green hornworm: rarely purple-brown, small black circles over thorax and between spiracles, seven pairs of oblique lateral lines, often edged with magenta or black above. Spiracles orange. Horn usually green with black lateral line.

Field Marks: This is a variable species and, where their ranges overlap, is easily confused in photographs with Spinx poecila (Northern Apple Sphinx). In well-marked specimens the fringes of the wings offer good clues to identification. In S. gordius the forewing fringes are mostly black with some white, and hindwing fringes are mostly whiye with some black patches. In S. poecila the forewing fringes are checkered black and white, while the hindwing fringes are almost totally white. See pinned specimens below.