Mud dauber wasp

5765  Can you tell me what this is and is it dangerous?

This is a thread-wasted wasp (Hymenoptera: Sphecidae), it appears to be Sceliphron caementarium , known as the black-and-yellow mud dauber. They are  of danger only to the spiders that they capture, sting, and paralyze as provisions for their larvae. See http://tinyurl.com/gpubxfa for much more detailed information on these fascinating creatures. Saugstad, retired entomologist; Sinks Grove, WV.