Nancy
These are a mating pair of Anchor Stink Bugs. The markings and colors do vary...some are black and white while other adults are red and black.
These are found in the eastern US and Great Plain states.
The adults feed on larvae of beetles, butterflies, and moths. The nymphs or young feed on larvae of the same insects especially the Mexican bean beetle larvae...so this is a beneficial insect to have in your garden.
Here are photos of the various color forms -
http://bugguide.net/node/view/6434/bgimage
