[2][3][4] It is native to the western coast of North America, from British Columbia in Canada to Baja California Sur in Mexico.

[4] In the United States, it can be found in Arizona, California, Colorado, Idaho, Montana, New Mexico, Oregon, and Washington.

As they mature, the larvae develop a series of oblique white stripes edged with purple down their sides, and the horn turns blue.

When mature and ready to pupate, the larvae create a sparsely silk lined chamber in the soil up to 10 cm (3.9 in) deep.

[3][4] S. perelegans larvae can be found on a wide range of host plants, including species of Arctostaphylos, Prunus, and Symphoricarpos, as well as Arbutus menziesii and Cercocarpus betuloides.