Phylum: Arthropoda (Arthropods)Beyond this I don't know. I did find two on BugGuide.net (here and here) that look like mine, but neither is identified to the species level, and only the second one linked is identified to the suborder level. The common species seems to be Phalangium opilio, but it doesn't look much like this one. At the bottom of this page at What's that bug? is a photo of a gang of harvestmen that are exactly what I think of when I think of the daddy long-legs of the woodpile and other similar locations. Very small, spherical body perched atop those long legs. The one I found today has a more oval body, and more elegant legs. The body is five millimetres long.
Class: Arachnida (Arachnids)
Order: Opiliones (Harvestmen)
I annoyed it a little and it left the doorframe and started off across the vinyl siding.
Not the sharpest photo, but the image below gives a better idea of the pattern on this critter's back.
These guys are nocturnal, and after I left this one alone for a while it found itself a hiding place where the siding meets the doorframe to hole up for the rest of the day. I hope that tonight it will go out and hunt down some rose chafers!