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A medium-size (2.8-3.5 cm wingspan) moth with rusty-orange forewings and grey-brown hindwings with an orange-brown fringe. The forewings are covered with a network of narrow faint dark lines along the veins and marking the normal lines and spots. The claviform, orbicular and occasionally the reniform spot are filled with lighter yellow-orange, but in most instances the reniform is bright contrasting white. Almost identical to A. americana, but most interoceanica have a white reniform whereas in most Alberta americana it is yellow or orange. The pale filling of the reniform of interoceanica is confined to the outer two-thirds of the reniform, but is more extensive in americana. Many specimens require an examination of the genitalia for positive identification. Both sexes can usually be identified by brushing and do not require dissection. Males of interoceanica lack the long digitus on the valve found in americana. Females of interoceanic have a deep notch on the 7th sternite, absent in americana.

The adults are nocturnal and come to light. There is a single brood each year, flying in late summer and early fall. The larvae feed on strawberry (Fragaria) and outbreaks on cultivated strawberries in Manitoba have been reported (Ayre, 1980). Eggs are laid on dead strawberry leaves in late summer and hatch in early May. The young larvae first feed on fruit stalks and leaf stems, sometimes clipping stems; later, they bore into the crown, killing the plant. The larval stage lasts from late May to mid-July. Outbreaks in Manitoba are sporadic but can be devastating.

Widespread, but the precise range is difficult to ascertain due to confusion of the two species. Amphipoea interoceanica occurs from Newfoundland west to BC, and south to North Carolina and Arizona. In Alberta it has been collected sparingly throughout the parklands and grasslands, west to Calgary.

Interoceanica is probably under-reported in Alberta owing to the difficulty in recognizing it among the much more abundant and often identical-appearing A. americana. Oddly, Bowman reported all Alberta Amphipoea as A. interoceanica, although with very few exceptions all specimens in his collection, as well as those available to him in the Strickland Museum, are actually A. americana. Most Amphipoea species are reported to use grasses and other monocots as hosts, but interoceanica is unusual in that it uses strawberry, a dicot in the family Rosaceae.