Detailed description available in link to the Mesogona revision (1995) linked below under citations. From the key to adult species - hindwing gray or with gray suffusion. (1)
Range
widely distributed in western North America - British Columbia to southern California and east to Idaho, western Montana, Nevada, Utah, Colorado, Arizona, New Mexico and Texas (1)
Mesogona subcupreata has copper-colored or reddish hindwings w/o the gray shading seen on olivata hindwings. (1)
Mesogona rubra has forewings and thorax brownish red to pink and copper-colored or reddish hindwings w/o the gray shading seen on olivata hindwings. (1)