Harvestmen have a pair of prosomatic defensive scent glands (ozopores) that secrete a peculiar smelling fluid when disturbed, confirmed in some species to contain noxious quinones. Harvestmen do not have silk glands and do not possess venom glands, posing absolutely no danger to humans (see below). They do not have book lungs, and breathe through tracheae only. Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. In more active species, spiracles are also found upon the tibia of the legs. They have a gonopore on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor). All species lay eggs.