Help! Western masked chafer is drowning.

Three things to note: 1.The northern masked chafer has more hair on it's backside than their southern cousins.
2. Southern masked chafers comes out at dusk, while their cousins come after midnight. I read they are in Southern California.
3. There is another species similar to the southern masked chafer called the western masked chafer or, Cyclocephala hirta. They come out around 8:30 p.m. which I now found out about. There is a Southern California version as well, Cyclocephala pasadenae