This looks like a cicada killer wasp. They are beneficial wasps that help to keep the cicada population down. They nest in dry sunny areas in the lawn and ornamental beds and are not particularly aggressive. They should be tolerated if possible.
They are not usually an indoor pest. http://extension.umd.edu/ipm/cicada-killer
This is very helpful and reassuring. We will downgrade our response from squashing to gentle shooing out. Thanks for the quick response!. We just moved in to a new house on South Mountain and it's rich in all kinds of insects and other amazing wildlife.
If these insects are coming in your house or nesting, you may want to send us additional photos. This is not an indoor pest.