Generally speaking, it refers to insects belonging to "cockroach" (scientific name), belonging to Arthropoda, Insecta, Cockroaches, commonly known as cockroaches, which are common medical insects. Only dozens of species will invade people's homes, and several species will be kept as pets and become food for pets. Most of them can only be seen in barren hills and wild forests or insect museums. Cockroaches are the most common cockroaches at home, and the largest cockroaches are about 5.0 cm (1.97 inches) long.