I've spotted several of these gorgeous black and yellow garden spiders around this year. Their distinctive markings, as well as their size (torso is about an inch to an inch and a quarter) make them look a bit scary, but they are harmless to humans. The females weave a zig-zag pattern into the middle of their large webs, thus giving them their other name---writing spider. There are lots of theories for why they do this. I wonder if E.B. White was inspired by these clever creatures when he created Charlotte. Look closely: Can you see "radiant" written in this web?
I made one of these lovely ladies from cut paper for my book, Scoot!, a few years ago.