Key to species of Psammopolia

1. Dorsal forewing gray; occurring from northern California to southwest Alaska .. 2

– Dorsal forewing gray brown to tan; occurring from Sonoma County, California to Baja California .................................................................................. 3

2. Orbicular spot oval; larger species (forewing length> 18 mm); male valve with broad expansion of mesial ventral margin; corpus bursae> 1.8× ductus bursae length ................................................................................. P. wyatti

– Orbicular spot nearly round; smaller species (forewing length <18 mm); mesial valve weakly expanded; corpus bursae <1.8× ductus length P. arietis

3. Orbicular spot incomplete, open along vein R and outlined in black scales; forewing dark gray brown to reddish brown; male antenna bipectinate; female corpus bursae> 1.5× length of ductus bursae .................... P. ochracea

– Orbicular spot complete, pale, without dark outline; forewing cream, tan, or medium gray brown; male antenna weakly biserrate; corpus bursae equal to ductus bursae length ................................................................................... 4

4. Orbicular spot round or ovoid; occurring on the central California coast north of Carmel; male cucullus wider than valve at base of clasper; female ovipositor lobes 0.4× length of ductus bursae............................... P. insolens

– Orbicular an elongate oval; occurring in San Luis Obispo County; cucullus width less than valve at clasper; female ovipositor lobes <0.3× ductus bursae length ................................................................................................ P. sala