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More About Scorpions ...
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Scorpions are distinguishable at a glance from all the other arachnids by having the last five segments of the body modified to form a highly flexible tail, armed at the end with a sting consisting of a vesicle holding a pair of poison glands, and of a sharp spine behind the tip of which the ducts of the glands open. Like spiders they have four pairs of walking legs; but the legs of the second pair form a couple of powerful pincers, and those of the first pair two much smaller flippers. They feed entirely upon animal food, principally upon insects such as beetles or other ground species, although the larger kinds have been known to kill small lizards and mice.
The large pincers are studded with highly sensitive tactile hairs, and the moment an insect touches these he is promptly seized by the pincers and stung to death, the scorpion's tail being swiftly brought over his back and the sting thrust into the struggling prey. Paralysis rapidly follows, and, when dead, the insect is pulled to pieces by the small nippers and its soft tissues sucked into the scorpion's mouth. Scorpions vary in size from about 2 cm to 20 cm; and the amount of poison instilled into a wound depends mainly on the size of the animal, though the poison of some of the smaller species is more virulent than in the larger species. On humans the effect of the poison is rarely fatal, though death has been known to follow in patients already in poor health.
In small scorpions, like those belonging to the genus Euscorpius, which occurs in Italy and other countries of South Europe, the sting is said to be as bad as that of a wasp; but in many tropical species acute pain, accompanied by inflammation and throbbing of the wounded part, follows. However, unless molested, scorpions are perfectly harmless, and only make use of the sting for the purpose of killing prey.
The belief that scorpions commit suicide by stinging themselves to death when tortured by fire is of considerable antiquity and is prevalent wherever these animals occur. It is nevertheless entirely false, since the venom has no effect on the scorpion itself, nor on any member of the same species.
Unlike the majority of Arachnida, scorpions are viviparous. The young are born two at a time, and the brood, which consists of a dozen or more individuals, is carried about on its mother's back until the young are large and strong enough to shift for themselves. The young in a general way resemble their parents and undergo no metamorphosis with growth, which is accompanied by periodical casting of the entire skin. Moulting is effected by means of a split in the integument which takes place just below the edge of the carapace all round, exactly as in kingcrabs, spiders and Pedipalpi. Through the split the young scorpion gradually makes its way, leaving the old integument behind.
Scorpions are of great antiquity. Their remains are often found in coal deposits of the Carboniferous Period, and no essential structural difference has been discovered between these fossils and existing forms—a fact proving that the group has existed without material structural modification for millions of years. These Carboniferous scorpions were preceded by others, now occurring in marine Silurian deposits, which evidently lived in the sea and exhibit some anatomical differences marking them off as a group distinct from their Carboniferous and recent descendants and attesting affinity with the still earlier marine Arachnida referred to the group Gigantostraca. Their legs were short, thick, tapering, and ended in a single strong claw, and were well adapted, it seems, like the legs of shore-crabs, for maintaining a secure hold upon rocks or seaweed against the wash of waves. The method of breathing of these ancient types is not certainly known; but probably respiration was effected by means of gills attached to the ventral plates of the body. At all events no trace of respiratory stigmata has been detected even in well-preserved material. These Silurian scorpions, of which the best-known genus is Palaeopzonus, were of small size, only two to five centimeters in length.
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Source: Wikipedia Read more about Scorpions
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