Arthropoda (Arachnida): The general name for all species of Arachnida (Arachnida or Arachnida). It is distributed all over the world except Antarctica. From sea level to 5000 meters above sea level. It's all from earth. Body length1~ 90 mm.
Spiders have both advantages and disadvantages for human beings, but as far as their contribution is concerned, they are mainly beneficial insects. The length of spiders ranges from 0. 05 mm to 60 mm.
The body is divided into chest and abdomen. Some species have breastplates at the back of the head and chest, and there are usually 8 monocular eyes (6, 4, 2, 0) at the front of the head and chest, arranged in 2 ~ 4 rows.