Arachnoidei

Arachnoidei is a subclass of arthropods that includes spiders, scorpions, mites, and ticks. These animals are characterized by having two main body segments, the cephalothorax and the abdomen, and by possessing eight legs. Unlike insects, arachnids lack antennae and wings. Their exoskeleton is made of chitin, and they breathe through book lungs or tracheae. Many arachnids are predators, utilizing venom delivered through fangs or stingers to subdue their prey. Others are parasitic, feeding on the blood or tissues of other animals. Arachnids are found in nearly every habitat on Earth, from deserts and rainforests to freshwater and marine environments. Reproduction in arachnids is typically sexual, with males transferring sperm to females. The young often undergo a series of molts as they grow, shedding their exoskeleton to accommodate their increasing size. Some arachnids exhibit parental care, protecting their eggs or young. The diversity within Arachnoidei is vast, with tens of thousands of described species.