This is a Japanese Beetle (Popillia japonica), in case you’re unfamiliar with them — beautifully colored, with their iridescent shells offset against the flower petals’ colors.  But hell on roses (and grapes, and birch trees, and…).
Japanese beetles are apparently not a big problem in Japan — they have many predators that help keep their numbers under control. Â But since their arrival in the U.S. early in the 20th century, they’ve been expanding their territory from their original “beachhead” in New Jersey. Â Courtesy of the warming climate, they made it to Colorado a few years ago. Â Luckily beetle traps are available via the internet, since local home and garden stores apparently haven’t taken notice of their arrival. Â Yet.
Seen in the War Memorial Rose Garden; Littleton, Colorado.