I live in Ambler, Pa.. north of Philadelphia. I see this big guy every night when I take my dog out. It just hangs out on the stone wall. I don't see any web near it though. Just wondering if I should be worried or let him do his thing.
If this pic doesn't help I can try to take another one tonight.
This appears to be a fishing/dock/nursery web spider (family Pisauridae); likely Dolomedes tenebrosus - see http://tinyurl.com/mfgda6 for an image. Like wolf spiders, they are active hunters that do not spin a capture web. Large specimens are capable of inflicting a painful bite if mishandled, but otherwise are harmless to humans.
