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. 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. Courtesy of the warming climate, they made it to Colorado a few years ago. Luckily beetle traps are available via the internet, since local home and garden stores apparently haven’t taken notice of their arrival. Yet.
Seen in the War Memorial Rose Garden; Littleton, Colorado.