A black phase female, collected in 2000 in Isabella Co., MI, in the historical range of Papilio canadensis Rothschild and Jordan, could be a result of recent introgression by P. glaucus L. If so, black females may become widespread, though infrequent, in the northern Lower Peninsula.
Blomberg, Goran E. D. and Herig, Edward Jr.
"A Black Phase Female in the Historical Breeding Range of Canadian Swallowtails (Lepidoptera: Papilionidae),"
The Great Lakes Entomologist: Vol. 47
, Article 5.
Available at: https://scholar.valpo.edu/tgle/vol47/iss1/5