Spiders vary in length 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 (some don't), and there are usually 8 monocular eyes (6, 4, 2, 0) at the front of the head and chest, arranged in 2 ~ 4 rows. There is a big chest plate on the ventral surface, and a lower lip between the two frontal lobes in front of the chest plate.

Most spiders have poisonous glands, with claws and claws. Most burrowing spiders move up and down, but they prey on the ground, and spiders that web in the air sweep around like pliers. No tentacles, no wings, no compound eyes, only one eye, usually 8 eyes, but there are also 6, 4, 2 eyes, and some even have no eyes. As far as the color and function of eyes are concerned, they can be divided into day and night.

Extended data:

Spider web construction rules:

Spiders first fix some silk around branches and corners. Among them, there is a special kind of silk, which passes around and weaves a little white silk in the middle, which is the center of the net. So it hangs a silk from the side, walks along the knotted silk, walks to the center, and then tightens it, and the excess length gathers on the white spot in the center, then walks from the center to the side, plus some spokes, in turn.

It adds a few spokes on one side and a few spokes on the other side to keep balance. The radial line of the spider divides a circle into equal numbers, and the angle between every two adjacent radii is roughly equal.

After drawing a circle with many equally divided radii, circle around the circle outward from the center of the circle, and make a spiral line on the radius with a very thin wire, which circles outward from the center of the circle and is parallel to each other, but the spiral line to the periphery is thinner from circle to circle.

Baidu Encyclopedia-Spider (Arthropod)

Baidu Encyclopedia-Spider Web (Spider Woven Web)