Every night for two weeks these beetles invaded our house, attracted to the light. They fly and are about 3/4 inch long. They crept in under the door, through open windows and around curtains. They would then proceed to crash into the wall repeatedly. Outside we could see perhaps a hundred clustered on any source of light. By day they disapeared, apart from the corpses of dead ones that littered the floor.
One day whilst watering the garden I discovered how they disapeared. Drenching the soil our basil is planted in, suddenly beetles started to appear in the puddle. As the water soaked into the soil the beetles were grounded and started looking for shade or burrowing back into the soil. Within one or two minutes they had all disappeared.