One of some million beetles of which something like about 8,000 are considered pests.
What are they doing? Are they damaging plants? Very probably good identification could be made quicker at your county office of the University of California Cooperative Extension service.

Here is a link that might be useful: UC CES

man i swear thats a lightning bug...

but i claim no expertise ... and i cant see its glowing butt ... and if i had not seen one yesterday.. a month early .. it would not have triggered ...

put one in a jar.. and flick a lighter at it at night ... and .. they tend to continually climb to the top of the jar.. no matter how many times you turn it over...

otherwise.. what he said ...

do you have them in SF???

ken

Here is a link that might be useful: link

Looks like one of the soldier beetles, also called downy leather wing beetles. If so, both the adults and larvae would be considered beneficials. You might be able to get an absolutely positive ID at the extension office.

looks like solider beetle is the winner! They turn out to be very close relatives of the lightning bug, so Ken, you weren't too far off either. I have about 50 of them on my fava beans, which is good because they are also covered in aphids. Go solider beetles!

http://bugguide.net/node/view/409325/bgpage

I'm glad the mystery is solved...a good group effort by all. By the way, grow power...just for the sake of YOU being correct...it's spelled "soldier", pronounced just like the military word. I 'd guess that they have that nickname because of the work they do controlling the 'enemy'.

Ken...you've really seen lightning bugs, already? That's incredible. I haven't spotted any down here, yet. I'll have to sit outside tonight and see what I've been missing.

you aint kidding.. its seems a month or two early ... mind you.. not lighting .. one just landed near me and kiddo ...

now.. we could be wrong.. as they look .. to me.. JUST LIKE THIS BUG .. we do not claim to be intimate with our bugs.. like some of you freaks.. lol ...

ken