This is a Mexican Bean Beetle. It is a member of the taxonomic family Coccinellidae, which includes Ladybugs. Almost all of the more than 5000 species in this family are predators, eating aphids and other pest insects, but a very few, such as the Mexican Bean Beetle, eat plants instead. This beetle eats bean plants, squash plants, peppers, and many other plants commonly found in vegetable gardens.