tortoise beetle

This is a really cool spotting! I especially like the second photo. I am pretty sure that this little beetle is, in fact, a Tortoise Beetle. Here is a picture of a Polished Lady Beetle to compare to yours: http://bugguide.net/node/view/250281 You can see that the protonum (area just behind the head) has black and white markings on the Lady Beetle, while your beetle is solid black. The lady beetle is also very shiny, your beetle appears to be more matte.