Tortoise beetles are small beetles that resemble miniature turtles. They are rarely found in high numbers in home gardens, so their feeding is primarily cosmetic. You’ll find them on plants in the Convolvulaceae and Solanaceae families, such as morning glory, potatoes, tomatoes, beans and peppers. The larvae of these beetles use their own frass and debris as a way of protecting and disguising themselves against potential predators (2nd photo below), and they can even raise the entire mass up and onto themselves from a special structure at the tip of their abdomen (1st photo below shows the pile of frass in the ‘lowered’ or flipped-down position).
Additional Information: Tortoise Beetles (University of New Hampshire)