I can identify that centipede.
There is a picture of a centipede on your site that someone from Tuscon, AZ sent in. It is the Giant Desert Centipede. I live in Ft. Huachuca, AZ (about 1 hour south-east of Tuscon) and found one on my front porch recently (see photo). There is a short description and a nice picture on the Saguaro National Park website. By the way, this centipede moves like lightning! We had a hard time catching it. I love your site. Thanks for the hard work! Best regards,
Ft. Huachuca, AZ
Thanks for the info, link and image of the variably colored Giant Desert Centipede, Scolopendra heros.