for the family ID. After your ID, I looked at the family info on http://bugguide.net/node/view/36236, which mentions the head being bend somewhat downward, & indeed this individual had the head bent downward on the first photos I took, but gradually moved it upward as I took several photos. I've added the first photo, showing the head bent downward.

I live in the San Diego area. My wife found a wasp exactly like yours that was caught in a drop of water. We observed it under a 2.5x Zeiss stereo microscope but it dried up and flew off before I could get a picture of it.

It was less than a millimeter long. About the same length as a garlic mustard seed, which I just happen to have harvested recently.

As it was cleaning its wings we observed a very shiny black abdomen with no apparent segments. It came to a slight point at the end. The body, head, and wings were EXACTLY like yours.

I don't believe it was the same one as the Platygastridae you point to in the link http://bugguide.net/node/view/36236.