Spider mites are not insects. They are arachnids, which also includes spiders, ticks, and scorpions. Adult mites normally have eight legs. They do not have antennae or wings. Spider mites are small, often difficult to see without a hand lens.
Color varies with species and even with the time of year.
Colorless red, brown, yellow and green spider mites are common. Spider mites puncture plant tissue with piercing mouthparts to feed on plant juices. Chlorophyll is removed along with plant fluids. As a result, plants infested with spider mites have a white or yellow speckled appearance. The plants look dull and unhealthy.