Hi:
Without seeing one, I can't tell you what species you have.  Many wasps are more visible at this time as year because food has become harder to find.  Is it possible to get a picture of one?

Thank you for the response.  I finally had the opportunity to photograph them.  They slowed down with the cold, we tried to block the hole in the wall where they are nesting but they found an alternate route.  They are still very active, especially in the maple trees and in my dahlia garden during the mid day.

Thank you for the response.  I finally had the opportunity to photograph them.  They slowed down with the cold, we tried to block the hole in the wall where they are nesting but they found an alternate route.  They are still very active, especially in the maple trees and in my dahlia garden during the mid day.

Thank you for the response.  I finally had the opportunity to photograph them.  They slowed down with the cold, we tried to block the hole in the wall where they are nesting but they found an alternate route.  They are still very active, especially in the maple trees and in my dahlia garden during the mid day.

Thank you for the response.  I finally had the opportunity to photograph them.  They slowed down with the cold, we tried to block the hole in the wall where they are nesting but they found an alternate route.  They are still very active, especially in the maple trees and in my dahlia garden during the mid day.

Hi:
This looks like a German yellow jacket. This link has more information:
http://ento.psu.edu/extension/factsheets/german-yellowjackets

Thank you for the information.  I just want to verify.  The nesting and behavior are similar to the german yellow jackets, but the size is different.  The description states they are about half inch in size.  I managed to kill two in the garage and they are almost an inch and a half in length when not curled up.  See photos below. 

Hi:
I apologize. I misidentified them. These are European hornets. Are you still finding them in the house?

http://ento.psu.edu/extension/factsheets/european-hornet

Yes. They are still active in the maple trees and gardens during the day and are nesting in the cement wall of a detached southern exposure garage. Hard to estimate , but there must be hundreds. I would like to know the best way to get rid of them and if 

Hi:
I hesitate in recommending control in a structure. As the fact sheet link states, they can chew through building material and if sealed in will try to get out. I don't know if there is something besides the cement that they might try to get through. Outside, if they are out of the way and are not handled aggressively, they are harmless. Also, due to their hard exoskeleton and quick mobility, spraying them outside usually doesn't accomplish much.

I also am hesitant to try to treat them in their current location which is deep inside the cement blocks of the garage.  As it is getting colder, I am assuming they will soon die off.  A few more questions - is there a bait trap that could be used to control them?  Is it possible to find the queen so I don't have a repeat of this situation next year?  What is the best antidote for the sting?  Thank you.

Hi:
The queen for your nest will die off. New queens were produced during the summer. From what I read, the nest site isn't renewed. There are a number of traps you can build to catch yellow jackets.  I think they would work for the hornets. The designs can be found on line. If you are allergic to stinging insects, then you need to be careful around them. It has been so long since I have been stung that I don't know what the most recent products exist for stings.