A small and relatively long-winged noctuid. It can be separated from other similar Alberta Lacinipolia species by its spring flight period, its predominantly yellowish-brown coloration, and the diagnostic but sometimes faint pale streak across the lower forewing. The reniform and orbicular are usually ringed with paler scales, and the later is usually oblong rather than round. The forewing fringe is partially checkered with pale scales at the veins. The hindwings are light grey-brown. The male gentalia have a large, long curved clasper, in Alberta species found only in longiclava and L. anguina. Like anguina, longiclava flies in the spring. Longiclava can be separated from anguina by the predominantly brown tones (grey in anguina), the pale longitudinal dash across the lower forewing, and by the more prominent checkering on the forewing fringe.