So I got some batteries for my flashlight, and after nightfall ( 9 or 10 ish) I approached the privet hedge, scene of previously unsolved leaf chewing. I heard what sounded like small dry things--dead leaves I thought at first--cascading down the shrubbery. Scanning the hedge, I quickly found the cause of the leaf damage: a small, dark reddish brown beetle with corrugated wings (elytra, actually, the thickened forewings typical of beetles) was chewing a typical pit in the margin of a leaf. She had a slightly elongated snout--aha, a weevil then! I reached out to grab her; she froze, lost grip of the leaf and tumbled dryly to the ground. What I had taken for leaves falling must be weevils taking evasive action. So it's likely they hide on the ground during the day, since the death drop from 6 feet up in the shrubbery would be really impractical if they didn't.
I had a short look around the rest of the garden that night, and I noticed this little weevil posing nicely on top of a tansy flower, proving whatever she is, she does not limit her nighttime activities to the privet hedges.
Next day I had a look under some rocks. Sure enough, second one I turned over had several weevils under it. They weren't moving; I could pick one up and it made no attempt to get away, or even wake up.
Insects of the Los Angeles Basin offers a very convincing description of the strawberry root weevil, Otiorhynchus cribricollis: a dark reddish brown, short snouted weevil about 1/4 inch long which is flightless and eats leaves (including privet) at night. The mystery pest is probably this species (although my specimen is larger, about 5/16 inch), or a closely related root or vegetable weevil. Interestingly, these weevils are parthenogenic, meaning they produce offspring (all female) without mating.
Otiorhynchus cribricollis is a bonafide pest, and you can get more information about its control at the University of California Statewide Integrated Pest Management site.