104 



BRANCH ARTHROPODA 



Size. — One giant species in Ceylon is 12 inches in length, 

 while American species are about 4 inches long. 



Habits and Distribution. — Scorpions are nocturnal. They 

 live in tropical and subtropical countries. Their sting is 

 dreaded by man, but seldom proves fatal. About twenty species 

 are found in North America. 



Order II. Phalangid'ea. — The members of this order look 

 like long-legged spiders, with small bodies. Closer observation 

 shows that the abdomen is fused with the thorax and not 



' Fig. 77. — Parts of a spider. 1, Under part of a spider's body: (, Thorax, 

 or chest, from which the eight h-gs spring, and to which the head is united 

 in one piece; /, fangs; p, palpi, or feelers, attached to the jaws; a, abdomen; 

 b, breathing-slits; .5, six spinnerets with thread coming from them. 2, 

 Front of spider's head; c. Eyes; p, palpi; I, front legs; h, hasp of fangs; 

 /, poison-fangs; j, outer jaws. (From Holder's "Zoology," .American 

 Book Co., Publishers.) 



joined by a pedicel, as in the spiders. The " harvest-man " 

 or " daddy-long-legs " is a familiar example. It frequents 

 shady places and feeds on small insects. 



They are a dull color, to fit their environment. So long as 

 they remain motionless their protective reseniblance conceals 

 them very effectively from their enemies. The respiration is 

 by tracheEe. 



Order III. Arane'ida, or Spiders (Fig. 77). — These are 

 arachnids with unsegmented abdomen joined by a pedicel to 

 the thorax. 



