Pseudoscorpion (false scorpion), common name for any of a group of small arachnids that look like little scorpions but have no scorpion's long tail and sting. You can meet Pseudoscorpions in leaf litter and soil, under rocks, and on intertidal algae. Some are phoretic-that is, they "travel" on other insects, such as beetles and flies. Some pseudoscorpion species live together with other arthropods, such as large beetles or ants. ~2000 species of pseudoscorpions are known.
The abdomen is elliptic with wide junction with the rectangular carapace, the shell-like covering of the head and top part of the body. The chelicerae, or grasping pincers, are little and are equipped with structures for cleaning the mouthparts. The pedipalps, smaller, pincerlike appendages, have poison glands opening at the tips. On some parts of the body are numerous trichobothria, or sensory hairs, which can sense small air currents. Pseudoscorpions move slowly, holding their pedipalps in front of them. They feed on small arthropods, which they subdue with poison and then tear apart with the chelicerae. Pseudoscorpion respiration occurs through 2 pairs of spiracles, or openings to the outside, leading to a tracheal system, branching tubes that bring air to the system. The third pair of walking legs has excretory glands near the coxae, or base segments. Pseudoscorpions are from one to several millimeters long (0,04 to 0,25 in).
The sexes are similar in appearance. They display a number of complex mating rituals. In some species, the male deposits a spermatophore, or sperm bundle, in the shape of a stalk on the ground. The female is attracted to the stalk chemically, or she may follow a strand of silk laid down by the male. She then positions herself over the spermatophore and takes it into her genital opening. In other species, the male may guide the female to the spermatophore and then position her over it by grasping her pedipalps. He then pushes against her to aid in the uptake of the sperm. The female produces eggs after successful sperm transfer. The eggs are held in a membranous sac attached to the female, and she gives them nourishment from her ovaries. The young emerge from the sac after shedding their skin, or molting, twice and undergo two more molts before becoming adults, which may take up to a year. From two to 50 young may be hatched per brood cycle. Pseudoscorpions live 2 to 5 years.