Speyeria hesperis and Speyeria atlantis are distinct species
S. hesperis and S. atlantis are distinct species; past reports of "intergradation" between them actually represent polymorphism of silvering within S. hesperis. S. atlantis is always silvered, and has a darker (chocolate-brown to blackish-brown) unh disc; it occurs in eastern North America as S. a. atlantis, then ranges as S. a. hollandi over the boreal forest/aspen parklands from Man. To Alta., where it is widely sympatric with S. hesperis helena; S. a. hollandi also occurs in the Rocky Mts. in Alta.-B.C.-NE Wash.-N Ida., where it is sympatric with S. hesperis beani and S. hesperis brico (B.C., ...
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