Nemoria darwiniata (Dyar, 1904). [7035]

Nemoria darwiniata darwiniata, collection of Carnegie Museum of Natural History. Specimen collected August, Shoshone Co., Idaho.

Nemoria darwiniata, collection of Carnegie Museum of Natural History. Specimen collected 24-VI-1987, Tehama Co., California. Note reddish brown discal spots on all four wings.

Nemoria darwiniata is a particularly widespread western species, known from Wyoming, Colorado and Utah in the Rocky Mountains west to the Pacific coast of California. It ranges as far north as Alberta and British Columbia and is found south to Baja California and Arizona. The species is relatively large among North American Nemoria, and its abdominal markings and wing markings are variable over its geographic range and across the two recognized subspecies. Notable characters to distinguish the species include a white to cream colored interantennal fillet with a reddish brown border along the back edge. Wings are typically a lighter shade of green and may have a slight blue or turquoise cast with substantial fine white striation. When present, discal spots on the wings may be prominent or reduced, and can vary in color from green to red.  Ferguson noted that the forewing usually shows a pink checkered fringe near the apex. This is apparent in the photo below, which also shows a deeper rose or crimson patch at the wing apex. On the west coast, Nemoria darwiniata can be easily confused with Nemoria glaucomarginaria especially with specimens of darwiniata that lack discal spots (which are consistently lacking in glaucomarginaria). For images of Nemoria darwiniata larvae, click here. 
Adam Ehmer wrote a valuable paper on host plants and larval plasticity that can be read on line here:
The host associations and developmental plasticity of Nemoria darwiniata

Nemoria darwiniata punctularia, collected July 2014, Leeds, UT.

Nemoria darwiniata forewing (above) with pink checkered fringe and crimson patch at apical angle. A dull discal spot is also visible in this image. Nemoria darwiniata punctularia at right from southern California. Note strong discal spots on wings and dark red-purple shading around abdominal spots.