Treehoppers (Hemiptera: Membracidae) are often easy to recognize thanks to their large pronota. In this family the upper surface of the first thoracic segment is expanded, covering the head and most of the abdomen. In many species the pronotum can take on a variety of ornate shapes. Some merely look humpbacked, but others are shaped like thorns, horns, spines, or in the case of this individual (Entylia sp.), the keel of a boat.
A couple of weeks ago I found several of these crawling around on goldenrod (Solidago spp., Asteraceae) and other asters at Pinckney State Recreation Area near Chelsea, Michigan. Although treehoppers feed on plants, only a few are of any economic importance as pests.