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There are three superficially similar marble species in the province. The Olympia Marble (E. olympia) is unlike the other marbles in that the green markings of the underside are quite reduced, with a banded rather than a blotchy appearance. It is also restricted to prairie grassland habitat. The Northern Marble (E. creusa) is slightly smaller than ausonides (wingspan of 24 - 36 mm compared to 30 - 48mm), and generally has more green than white on the hindwing underside, in a more broken rather than banded pattern. Our populations have been variously assigned to subspecies mayi (Bird et al. 1995, Guppy & Shepard 2001) or ausonides (Layberry et al. 1998).

The egg is orange and elongated, tapered near the tip. The mature larva is greyish-green and black-spotted, with a lateral white and yellow subdorsal stripe (Guppy & Shepard 2001). The pupae are light brown with darker longitudinal lines, and have a pointy, elongated head projection (Guppy & Shepard 2001).

The larvae likely feed on a variety of wild mustards in Alberta; females oviposit on Drummond's Rock Cress (Arabis drummondii) in the Peace River region (Bird et al. 1995). Hooper (1973) is one of the few sources to report adult nectaring, which occurs at the flowers of larval hostplants.