1, the appearance is different: scarabs are mostly nearly round, with hard, smooth and metallic shells, while longicorn beetles are rectangular, with larger length and width than scarabs, and their shells are not as hard as scarabs, and their surface luster is poor.

2. Different ecological functions: Scarabs are beneficial to agriculture, feeding on agricultural pests helps to control other pests, while longicorn beetles feed on rotten wood, which helps to decompose dead wood.