This false click beetle was photographed at Upper Oriflamme Canyon at an elevation of about 3800-4000 ft. This area has many live oaks. I identified it as P. witticki on a combination of reasons: Harvard type, http://insects.oeb.harvard.edu/mcz. I brought both images into Photoshop and they agreed in every detail I could find except color: in size, shape, structural lines and curves of pronotum and elytra, first three antennal segments, base of the pronotum with short shaggy hairs. I then found an image of P. cervina that also occurs in CA at www.elateridae.com. It was not nearly as close a match. It was not as robust, the anterior of the pronotum where it meets the head is more curved, not as straight across, and the antennal segments were not the same.
The final consideration was distribution.I found an article by G. Alpert, 1972 in the Coleopterists Bulletin v. 26 on aggregations of over 500 beetles of P. witticki on one live oak tree in San Diego County, Oakzanita Springs Park, at an elevation of about 4000 ft. in May and June. The site less than 10 miles north of where we found this beetle in almost the same habitat at the same time of year.
Of course, from a photograph I could not determine details of sternum or genitalia and in this insect all other considerations may not matter.