CHAPTER VIII 



SCORPIONS. SPIDERS. CENTIPEDES AND MILLIPEDES 



THE class Arachnida includes the Scorpions, Spiders and Mites 

 creatures which breathe by means of " lung-books," tracheae, 

 or a combination of the two systems of respiration. They have 

 no separate head, the head and thorax being fused together into 

 one division termed the cephalothorax. 



Scorpions are found in all the warmer parts of the globe. In 

 India and West Africa some species grow to a very large size, and 

 are really formidable-looking creatures, often measuring 9 inches 

 in length. The body of a scorpion is broad and long, ending in 

 a long, jointed tail. The head and shoulders (cephalothorax) are 

 covered by a sort of carapace, reminding one of the carapace of 

 a lobster. Near the centre of the carapace are the two simple 

 eyes, usually surrounded by several groups of smaller eyes number- 

 ing from five to two. The front portion of the shield also bears 

 a pair of stout nipping jaws (chelicerc?), and a pair of appendages 

 (termed pedipalps) armed with strong, crab-like claws. The tail 

 ends in a sting containing a poison gland, and is usually carried 

 curled over the back When the scorpion is taking a walk. When it 

 stings the creature suddenly straightens its tail and strikes down- 

 wards, so that the old notion that a scorpion surrounded by a 

 ring of fire would deliberately sting itself to death is practically an 

 impossibility. In such circumstances the probability is that the 

 poor creature, Unable to escape from the great heat, would become 

 greatly excited and jerk and flourish its tail over its back in its 

 terror ; and these movements were believed to indicate that the 

 scorpion Was trying to sting itself on the head. Actually, 1 "as 

 poisonous snakes cannot kill themselves or others of their own 

 species by their venom, so scorpions cannot injure by their poison 

 either themselves or other scorpions." 



1 Chambers's Encyclopaedia. 

 126 



