About Macronoctua onusta Grote, 1874
Macronoctua onusta is a large moth colored brown and smoky dark gray, with a forewing length of 18–21 mm. Its forewing is broad with a scalloped outer margin and a black streak along the reniform spot. The forewing is dull brown, with broad smoky dark gray suffusion on the costa, in the cell, and also in the terminal area and fringe. The antemedial and postmedial lines are thin and dark gray. The antemedial line extends far lateral above the posterior margin. The median line is dark brown, and is strongly arched across the brown median area below the cell. The postmedial line is jaggedly zigzagged on the anterior portion of the wing, and straight from the anterior cubitus vein to the posterior margin. The subterminal line is only visible as the transition between the brown subterminal area and the black terminal area. A black line marks the terminal area. All three forewing spots are outlined in thin black. The orbicular spot is a small oval. The reniform spot is large and asymmetrically kidney-shaped, with its lower end curved toward the outer margin and touching the postmedial line. It has a darker posterior outline that forms a straight black line below the cubital vein. A spike-like process extends toward the base from the posteromedial end of the reniform spot. The claviform spot is small and elongate, with a rounded end. The hindwing is dirty brown-gray with a slightly darker discal spot, slightly darker veins, and a scalloped terminal line. The hindwing fringe is light gray with a brown base. The head and thorax are uniform even smoky dark gray. The male antenna is broad and bead-like. This species can be easily identified by its large size, dark gray anterior and lateral margins, and the distinctively shaped reniform spot and postmedial line. Similar dark brown moths do not have the dark posterior outline, the spike from the medial reniform spot, or the postmedial line with serrate anterior and straight posterior segments.
