One of the chafer beetles, a common and typical pest of much of the world. These adults have come from grubs in the ground, usually where there is a nice lawn languishing in the sun. You might want to investigate the effectiveness of Milky Spore inoculant for your vicinity and soil (it doesn't work everywhere). Handpicking is an effective way to get rid of adults, as is insecticidal soap. I've heard good things about neem as a control for beetles but can't speak to that myself.