This tiny, black and white spotted cixiid planthopper does not seem to have a common name. Bothiocera cognita is about 3-5mm long, and appears to range through the southeastern US. Other than that, it’s a nondescript little planthopper, without even a Wikipedia entry.
Planthoppers, in general, live on, and eat plants, eating the roots as nymphs and the leaves and stems as adults. As their name implies, they can launch themselves forward at great speed if startled. Otherwise, they hang out cautiously on the leaves they’re feeding on, trying not to attract attention.