treatment as subspecies follows Ferguson (1971) and Tuskes et al. (1996) (1)
Size
male forewing 42-48 mm; female forewing 47-54 mm
larva length to 80 mm
Identification
Adult: compared to E. i. imperialis, upperside of all wings have heavier sprinkling of purple-to-black dots, and underside of all wings have well-defined PM line (2)
Larva: abdominal segments have two paired rows (dorsal and dorsolateral) of large shiny white scoli (fleshy protuberances); spiracles white
Range
northern third of Michigan's lower peninsula, southcentral Ontario from Sault St. Marie in the west to Ottawa in the east, upstate New York, and southeastern Quebec near Montreal; single records from Vermont and the Thunder Bay area of Ontario; type specimens collected in Cheboygan County, Michigan. Populations in northeastern New York and Vermont could be considered somewhat intermediate to E. imperialis imperialis(1)
(northern limit of subspecies imperialis range includes southern Maine, southern New York, lower Niagara peninsula of Ontario, central Michigan, southwestern Wisconsin, and central Iowa)
Habitat
mostly sandy pine forests and pine plantations (1)
Season
adults fly from June to August
larvae from July to September
Food
larvae feed exclusively on conifers, mainly White Pine and Red Pine; also recorded on Jack Pine, Scotch Pine, and White Spruce
adults do not feed
Life Cycle
one generation per year; overwinters as a pupa in the soil
Remarks
uncommon and local in Ontario; rare and local in Quebec and elsewhere within its range
mate and come to lights mostly between midnight and 2:30am, about an hour later than E. imperialis imperialis(1)
See Also
nominate subspecies imperialis adult is larger (male forewing 47-59 mm; female forewing 58-68 mm) and wings have lighter spotting above and faint or absent PM lines below
nominate subspecies imperialis larva is larger (95-115 mm), dorsal and dorsolateral scoli much smaller or lacking, and spiracles usually yellow
Internet References
live adult images plus description, larval foodplants, flight dates (Lynn Scott, Ontario)
detailed subspecies account including description of adult and larva, distribution, larval foodplants, biology (Paul M. Tuskes, James P. Tuttle, Michael M. Collins, "The wild silk moths of North America: a natural history of the Saturniidae", courtesy Google Books)
original description of subspecies by Charles Michener (Journal of Kansas Entomological Society, 1950, courtesy jstor.org)
live larva image showing green form (Bill Oehlke, silkmoths.bizland.com)
common name reference and status in Ontario (Natural Heritage Information Centre, Ontario Ministry of Natural Resources)
