Eastern Tent Caterpillar
Yup, I've found two of these webs in my crabapple trees so far this spring. Don't panic. I used a long stick to wind up the nest and remove it from the tree. This year I even remembered to put a tarp on the ground below the nest and to stand upwind while I did the deed. No more worms in MY hair.) Here's a site that shows what they look like and how to stop 'em: http://www.urbanext.uiuc.edu/bugreview/easterntentcat.html.
The Hardiest Palm in Philly
If I had a nickel for every time someone asked me to suggest a hardy palm tree (or a hardy banana tree for that matter), I would have some coins to rub together and my answer would still be the same, sadly, no dice. But to be fair, it depends what protective steps you are willing to take, what you consider as a standard for hardy, and what you consider to be a palm tree or at least a palm plant. This Hardiest Palm site profiles some palms found to be hardy in the Philadelphia area and includes links to more hardy palm sites. What fun!