Found at midday resting motionless within a flower of the dune evening primrose Oenothera deltoides. When I tried to gently open its wings it flew to a nearby plant leaf, where this series of photos were taken. Another individual resting within a flower appears in the thumbnail below:



Upon first seeing these moths in the field, I immediately guessed they were Schinia. Later, at home, I searched the web for species using evening primrose as host and quickly encountered Schinia florida. My initial impression from the BugGuide data page was that this was an eastern species, but I soon found the maps on this MPG web page, as well this Pacific NW Moths web page, and this Butterflies & Moths of NA web page...all indicating that S. florida reaches parts of the far west. Still I found no records in west-central CA, and what's more, the flight period for S. florida was given as July-August, and I had just photographed this moth in early March. Moreover, S. florida has hind-wings white above, whereas the moth here has hind-wings dark above (just partly visible in the photos).

But further searching turned up two more candidates...both with dark hind-wings:

1) S. lynda, known only from Lake Co., Oregon, according to this Pacific NW Moths page (although the map on this MPG page...indicates a record from southern CA); and
2) S. felicitata, with records from s CA, s NV, and w AZ (see MPG page, Butterflies & Moths of NA page, BOLD Systems page, and this PDF of "The Life History of Schinia felicitata (Noctuidae)" by D. F. Hardwick from 1967).

While the Pacific NW Moths web page stated the flight time of S. lynda is May and its host is unknown, the Hardwick paper(1) stated the flight period of S. felicitata is March-April, and its host is Oenothera deltoides! So my best hypothesis is that this is S. felicitata. And if it is, it seems this may be a northwestern range extension in cismontane California. This would be interesting, since the Monvero Dunes are an isolated dune habitat in the inner Coast Range, disjunct from similar desert habitats of locations recorded for this moth on the map here...and in the online collection listings from the Essig Museum and the Cal. Acad. of Sciences.