XIII 



ARACHNID A 



197 



FIG. 131. The Common Harvestman 

 (Phalangium opilio] $ . 



Order II. : PHALANGIDEA (THE HARVESTMEN) 



The Harvesters, or Harvestmen, are often mistakenly 

 called spiders, from which they differ widely in the form of 

 the body. In them 

 there is no con- 

 striction between 

 fore and hind 

 body, and also 

 the abdomen is 

 clearly segmented 

 and bears no spiri- 

 nerets. They 

 breathe by tra- 

 cheae only, two 

 spiracles opening near the base of the fourth pair of legs. 



The Common British 

 Harvestman has an al- 

 most spherical body and 

 very long legs. It fre- 

 quently loses a leg, but 

 seems little disturbed by 

 the loss. Harvestmen feed 

 on aphides and small in- 

 sect grubs. The females 

 lay their naked eggs in 

 holes in the ground, or 

 under stones. 



Order III. 

 ACARINA ( MITES) 



Acarina or " Mites " 

 are usually minute Arach- 

 nids in which the abdo- 

 men and thorax are united 

 by a broad junction, and 

 the abdomen is unseg- 



FIG. 132. Lime leaf with Gall. 

 A, Lime leaf with "Nail Galls," g (nat. size); B, mented. 

 a longitudinal section through one Nail Gall The 



(enlarged) ; C, one Nail Gall Mite (much en- 

 larged). 



young larva at 

 first has usually three 



