Orthosia terminata (Smith, [1888])




Orthosia terminata is a rarely collected medium-sized (FW length 16 mm) mottled olive gray species that flies in southwestern Oregon in the spring. The forewing is slightly darker medial to the subterminal line and at the median line, and lightest in the terminal area. The strongly mottled pattern obscures the lines and spots, although the transverse lines are evident as dark spots along the costa and the postmedial line is marked by paired dots on the veins that are visible in most individuals. A series of dark spots between the veins marks the terminal line. The light outline of the reniform spot is evident in some specimens, both the orbicular spot is barely visible and the claviform spot is absent. The hindwing is medium olive gray with darker gray discal spot and veins. The fringe is light whitish gray. The head and thorax are mouse gray without tufts or ridges. The eye is covered with fine hairs. The male antenna is moderately bipectinate.

Orthosia terminata can be identified by its mottled olive-gray color and light terminal area and is unlikely to be confused with any other spring-flying moth in southwestern Oregon.


This species is narrowly endemic to dry oak savanna, oak woodlands, and mixed hardwood-conifer forests with oaks at low elevations in California and southwestern Oregon in the Siskiyou region.  It appears to be very rare in the Pacific Northwest, but is more common in California.


Pacific Northwest

Orthosia terminata is limited to the Siskiyou Mountain region of southwestern Oregon in our area.


The range of O. terminata extends south through California to near the border with Mexico. It is most commonly found along the Pacific Coast but also occurs in the northern part of the Sierra Nevada.

Life History


No information is presently available regarding larval foodplants of this species, but it may feed on oaks (Quercus spp.) in the Fagaceae based upon the habitat.


This moth flies in the spring like most other species of Orthosia and should be sought from mid-March through April. It is nocturnal and comes to lights.

Economic Importance




Moth Photographers Group