Nemoria obliqua (Hulst, 1898). [7037]
Nemoria obliqua is a widespread species of the southwestern United States, recorded extensively from Colorado, Arizona and New Mexico. It stands out as a very bright olive grass green moth with strong, often broad white am and pm lines. The wing color is typically a deep and even green and without any white striations, a characteristic which can help distinguish it from Nemoria caerulescens, which overlaps it in certain areas of its geographical range. Nemoria obliqua also has a strong green coloration on the first four segments of the ventral surface of the abdomen (see photo below at right).
Ferguson tentatively established a distinct subspecies, Nemoria obliqua hennei, based on some minor genitalic differences and an apparent discontinuity in the range of collected specimens conforming to the hennei subspecies form. Specimens of Nemoria obliqua hennei were collected in California and Nevada, in the Sierra Nevada mountains. In 2005, Friends' Central researchers collected individuals of Nemoria obliqua with unusual wing lines at Capulin, NM; genitalic dissection revealed characteristics closely matching the form of Nemoria obliqua hennei figured in Ferguson 1969. Nemoria obliqua collected the same week from another New Mexico site just 200 miles south in the Sandia Mountains matched the form of the nominate subspecies Nemoria obliqua obliqua. It seems likely that the differences in genitalia and wing patterning are within the normal range of intraspecific variation, and that the populations of Nemoria obliqua should be treated as a single group ranging from New Mexico to California.
Ferguson tentatively established a distinct subspecies, Nemoria obliqua hennei, based on some minor genitalic differences and an apparent discontinuity in the range of collected specimens conforming to the hennei subspecies form. Specimens of Nemoria obliqua hennei were collected in California and Nevada, in the Sierra Nevada mountains. In 2005, Friends' Central researchers collected individuals of Nemoria obliqua with unusual wing lines at Capulin, NM; genitalic dissection revealed characteristics closely matching the form of Nemoria obliqua hennei figured in Ferguson 1969. Nemoria obliqua collected the same week from another New Mexico site just 200 miles south in the Sandia Mountains matched the form of the nominate subspecies Nemoria obliqua obliqua. It seems likely that the differences in genitalia and wing patterning are within the normal range of intraspecific variation, and that the populations of Nemoria obliqua should be treated as a single group ranging from New Mexico to California.
Another interesting variation within the obliqua species relates to the variability in spacing and patterning of the line markings on both forewings and hindwings. Nemoria obliqua was named for the oblique angle formed by the straight white am line on the forewing. The distance between the pm line and the am line on the hind margin of the forewing is highly variable, with the lines often set far apart, but sometimes approaching each other very closely where they meet the margin. In the most extreme cases, the two lines may even converge in front of the hind margin and form a U-shaped pattern on the forewing (photo below, right). A similar sort of plasticity in the line markings on the hindwings can be observed in other specimens. The am and pm lines may be irregularly convex, and may also join into a U-shape, sometimes with a crescent shaped tail beyond the curve of the U (see photo below at left). This crescent may align with a transverse white line on the abdomen to complete a pattern that extends from one hindwing across the abdomen to the opposite wing when the wings are held out at rest.
For additional images of immature stages of Nemoria obliqua, click here: Nemoria obliqua, larvae and pupae.
For additional images of immature stages of Nemoria obliqua, click here: Nemoria obliqua, larvae and pupae.