We have recently been invaded by a swarm of wasps that I have not been able to identify. Does anyone here know what they might be? Here are the details as I have them:

They are black, with the body of a dauber (somewhat), I have not been able to find any nest that they are coming from, but at night, they swarm up on my porch in the 100s. They have been numerous enought to turn a white post on my porch black and 2 wasps deep at times. I have killed them about 4 times this year but they keep coming back. They swarm around my trees during the day, and stung my niece a few weeks back when one got caught in her clothes. They otherwise don't seem superagressive, and the sting wasn't as bad as a yellowjacket or red wasp. Without finding a nest anywhere, I haven't been able to figure out what they are.

HELP!!

Jason

This has been a good site for helping me to i.d. wasps:

http://www.conservation.state.mo.us/nat ... /index.htm

This is another site:

http://entowww.tamu.edu/fieldguide/

I hope this helps