Judging from your photos, this insect is called the cloud-spotted gill beetle. Scarab is a plant pest, which is harmless to people. The cloud-spotted gill beetle is generally 36~42 mm long. The body color is brown. Yellow-brown or white scales have three longitudinal bands in the shape of "M". It belongs to COLEOPTERA, and its white scales on COLEOPTERA are like clouds and marble lines, so it is also called marble scarab.
The cloud-spotted gill beetle has phototaxis and will be attracted by the lights in the house at night. Usually hide during the day and come out at night.
Scarabs do great harm to plants. Its adult will eat the leaves of almost all kinds of plants, and in severe cases, it will eat all the leaves of a tree. Its larvae mainly eat the roots of trees or crops.