Gasteracantha cancriformis spiders spin large webs under the tree branches in my yard, generally at just about the right height for people to walk face first into them - YUCK! OH, and they bite. It's not a horrible bite, but it's very uncomfortable for several days.

When they get me, I usually end up with a red welt on my shoulder that itches and aches. I can't absolutely say it's these spiders that have bitten me, since when I manage to get myself into a web I'm busy jumping up and down and brushing web off, but it's usually after getting tangled in one that I end up with the ouchey spot right about where the spider would have been bothered by the edge of my shirt. I'm not willing to go play with one to let you know for sure.

Gasteracantha cancriformis spiders look like crabs, so they're often called crab spiders, but those are different critters. These red black and white spiders are spiny orb-weavers.