This is near Phoenix, Arizona. This guy has been showing up on my back porch the last few nights, and then is gone in the morning. The body is about half an inch long, and the legs are well over an inch. It seemed all black, no markings. (Some of the pictures are with the flash reflecting).
CLOSED: Spider Identification
This spider has the general appearance of a comb-footed/cobweb spider (family Theridiidae) in the genus Latrodectus (widow spiders). If so, it should have a reddish/orange marking on its underside - see http://bvpestcontrol.com/wp-content/uploads/southern_black_widow-640x270.jpg and https://i.pinimg.com/originals/ea/8f/cc/ea8fcc79fc038431fb130105b32e50f5.jpg for examples.
Yikes! Thanks, Flapdoodle, for your help. I got a pretty good look at the underside and couldn't see any markings. But it was dark, so I will go out with a flashlight tonight instead of relying on the porch lights. I will update if I can get another look tonight.
Also, see if you can get any clear pictures of both its top (dorsal) and under (ventral)sides without a flash.
Okay, you were right Flapdoodle! It was definitely a widow. I couldn't get a clear picture of the ventral side; I wasn't able to hold the camera steady enough for a slow shutter speed in the dark. The hourglass was more of a faint burnt orange, but getting up close with the flashlight, it was unmistakable.
There were a couple things that threw me off one: one it was big, over two inches. And two, the abdomen didn't look shiny like the rest of it, it seemed covered with a short gray fuzz. Do they molt?
Spiders do molt periodically, but this usually stops once they reach full size.