Arthropods (Arthropoda)---Insects (Insecta)----Beetles (Coleoptera)---Polyphaga---Cucujoidea----Ladybird beetles (Coccinellidae)----Coccinellinae----Coccinellini----Macronaemia----M. episcopalisThis ladybird is a marsh-dwelling species, appearing in areas near water with many Cattails. The Episcopalian ladybird (apparently has no recognized English name, but I still use one) is probably the second most common marsh-dwelling species, with the commonest being the Marsh, Water or 19-spotted ladybird (Anisosticta bitriangularis) . This species appears in April and disappears somewhere around October (as in "disappears" it is probably hibernation but I will have to check that at some point).
The stripes on the elytra seem to be typical of marsh-dwelling insects as they probably match the cattail and sedge background. John Acorn writes that the Episcopalian "is another unconfirmed aphid predator"; it seems many of Alberta's species are widely unknown. It is understandable however, how are you supposed to find out unless you see one eating an aphid? Put in a container with many different insects?