This little plant hopper is in the genus Acanalonia. They are common throughout Missouri as well as most of the United States. Look for them in grassy areas or gardens where they blend in well with leaves and grasses. Most leaf hoppers feed on plant juices. Their common name of plant hopper comes from their ability to hop great distances (for their size) when disturbed.
This little hopper is a nymph, and I am unsure exactly which species it will be when it finally reaches adult size, but I suspect it will be this one:
Don't you just love the horns on this fellow? Maybe he should be called the Devil Leaf-Hopper. It seems leaf hoppers, or plant hoppers come in all sizes, colors and variations.
Red-Banded Leaf Hopper.
Here is another unique color form, this little guy (gal) was a delicious shade of blueberry, with darker stripes.
Seems there is no end to the diversity. If you can imagine it, you will find it.