of Encyclops with that elongate body and pronotum, but just a guess

many problems:
Encyclops caeruleus (Say, 1826) has pale legs and is widespread in the East;
Ecyclops californicus Van Dyke, 1920 is all pale and lives in California...
cf. http://plant.cdfa.ca.gov/byciddb/thumb.asp?g=Encyclops

Nonetheless, no other genus seems to be possible...

our Encylops californicus specimens are metallic green, blue, or purple, but they all have completely pale legs and antennae. Definitely a mystery.

One consideration has to be Leptalia macilenta. Color is given as dark greenish to brown metallic. The elytral pattern is very variable and may be all dark to pale vittate. When it is all dark the legs are dark too. One character that separates it from Encylops are the shallowly emarginate eyes.

would like to see that pronotum a little better, but I think its a good call...I was having issues with the leg color, but we dont have either species around here, so had nothing to compare to.

I checked our specimens of Leptalia macilenta. Out of about 30, only three were dark but they are a very good match to the picture.

I included it in case it might help. This is the same as the first shot, but at full blurry cropped in size.

in this picture are the eyes clearly emarginate...

P.s. I have identified as Leptalia another specimen ( http://bugguide.net/node/view/250363#375803): what do you think of it?

All have emarginate eyes, the question is whether they are shallowly or deeply emarginate. This one appears to have a broad, shallow emargination (as in Leptalia), while my Encylops have it more "V" like.

As mentioned, the color and markings on Leptalia are very variable. The specimen you identified does fall within the range of variation described, and actually is a better match color-wise to the specimens in our collection.

I love it when there's a mystery. :)