http://en.wikipedia.org/wiki/Vespula_vulgaris

Relative to yellowjackets (which I mistakenly considered hornets) and wasps, the matter of identification is, so far, still somewhat confusing. I now realize, however, that yellowjackets are vespine wasps… and not hornets, and that paper wasps are a subfamily of Vespidae (eusocial wasps). Hornets and yellowjackets share the same family and subfamily (Vespidae Vespinae). Actual paper wasps are Vespidae Polistinae.

Some yellowjacket ID data:

http://wasps.ucr.edu/waspid.html

http://www.santarosa.edu/lifesciences2/identifi.htm

Paper wasps (Polistinae) are often confused with yellowjackets (Vespinae), which are ordinarily somewhat more aggressive. Yellowjackets, of course, are ordinarily mistaken for bees even though these two organisms bear only a relatively slight resemblance to one another.

Many hymenopterans (including bees and bumblebees — and, I suspect, other insects such as mantises (Mantodea) and jumping spiders (Salticidae)) have advanced face-recognition abilities:

“Wasps and humans have independently evolved similar and very specialized face-learning mechanisms, despite the fact that everything about the way we see and the way our brains are structured is different,” Sheehan said. “That’s surprising and sort of bizarre.”

Facial Recognition in Wasps:
http://www.sciencedaily.com/releases/2011/12/111201142756.htm

Common Wasps: (also known as a yellowjacket, apparently):

http://en.wikipedia.org/wiki/Common_wasp

Yellowjackets:

http://en.wikipedia.org/wiki/Yellowjacket

Paper Wasps:

http://en.wikipedia.org/wiki/Paper_wasp