XIV. SCORPIONS, SPIDERS, AND TICKS 



Cla. 



ss. 



Arthropoda {continued) 



— Arachnida (arachie, spicier) 



Although these animals are closely related to tlie crus- 

 taceans, they differ from the latter, in not having their 

 bodies inclosetl by a calcareous crust. They differ also in 

 living, with few exceptions, on land. The more familiar 

 examples of this class are the spidei's, present everywhere, 



the ticks, on cattle 

 and dogs, and the 

 mites on fowls and 

 plants. 



Scorpions. — Al- 

 though these ani- 

 mals are thought to 

 he yevy venomous, 

 it is difficult to find 

 an authentic case of 

 death l^y a scor- 

 pion's sting. The 

 larger species in th.e 

 tropics, however, cause serious wounds. The body of the 

 scorpion is flivided into two distinct regions, the cephalo- 

 thorax and the abdomen. The abdomen consists of an 

 enlarged portion, next to the thorax, called the preabdo7nen, 

 and a long, slender tail-like portion, the postabdovien (Fig. 

 82). The scorpion has two pairs of jaws and to one pan- 



144 



I'^iG. 82. — Scorpion. 



