102 



AEACHNOIDEA. 



is no true metamorphosis ; but growth takes place by a series 

 of ecdyses, the young resembling the adult in general form. 

 The ova develop rapidly. The three divisions are characterised 

 as follows : — 



i. Araneida or Spiders (fig. 39, a) have the head and thorax 

 united into one piece, the cephalothorax(o), the abdomen (a) being 

 distinct. Eyes are represented by clusters of ocelli (fig. 39, b, /). 



Pia. 89. —House Spidee. 



A, Male of House Spider {Tegem^jjria, civil/Is} enlarged : c, cephalothorax ; p, maxillary 

 palpi ; a, abdomen, b, front of head : /, ocelli ; 91, mandibles, c, under side of head : 

 TO, true jaws ; I, lower lip. D, diagram of one of the air chambers. (After Blaokwall, 

 from Nicholson.) 



ii. Scorpionidoe have the anterior palpi elongated like legs, 

 and provided with nippers like the claws of a crab. The ab- 

 domen may have the last six segments elongated and formed 

 into a spurious tail. 



