What kind of bug is this? Thumb size. What's its name?

ground beetle

Eupolyphaga is a real Chinese terrapin.

[1] Eupolyphaga sinensis alias: Eupolyphaga sinensis, Eupolyphaga sinensis, Eupolyphaga sinensis crossing the street, Eupolyphaga sinensis, etc. It belongs to insects, with flat body, brown and black, winged males and wingless females. It often moves in the soil at the root of the old-fashioned earth house. It is a Chinese herbal medicine that is in short supply in the market. With the destruction of the natural environment and the increasing market demand at home and abroad, the wild Eupolyphaga sinensis has been far from meeting the market demand, and the market price of Chinese herbal medicines in Bozhou has increased year by year [2]. Also known as insect stinger (zhèchóng), commonly known as water turtle. Dry female of Eupolyphaga Seu Steleophaga or Scarab. After fishing, blanch, dry or dry.