Spittlebugs (Family Cercopidae), also called Froghoppers, are tiny bugs that feed on plants by piercing the plant and sucking its juices. Spittlebug nymphs are recognized by the nest of "spit" they make. Adults are recognized by way they hold their wings over the body as a tent to conceal their legs and other body parts. Unfortunately, to the casual observer, they look just like leafhoppers.

For experts, spittlebugs have one or two stout spines on the hind tibiae, while leafhoppers have one or two rows of spines on the hind tibiae.

Spittlebugs can be disease vectors for plants, but these tiny creatures are entirely harmless to humans.

Spittlebug nymphs suck fluids from plants, then excrete it as liquid feces. They mix the feces with other body excretions to make their sticky spit, then whip it up into a froth using the tail-like structure on back end. Spittlebug nymphs live inside the spittle mass where they receive some protection from predators and maintain a humid environment.

For more information, see BugGuide.net and Wikipedia.