PHYLUM ARTHROPODA 



665 



into the web by means of the 

 posterior legs. There are six 

 or eight eyes on the carapace. 



In the spider-like Phalangida, 

 or " Harvest-men," the cephalo- 

 thorax is not constricted off 

 from the abdomen. The cheli- 

 cerae are chelate, the pedipalpi 

 short and leg-like, the legs long 

 and slender. 



In the Acarida, or Mites and 

 Ticks (Figs. 546 and 547), the 

 distinction into regions is no 

 longer recognisable. The form 

 of the mouth parts varies some- 

 what in the different families. 

 Sometimes the basal portions of 

 the pedipalpi form a sucking 

 proboscis enclosing the stylet-like chelicene, modified to form 

 piercing organs; sometimes these appendages are claw-like or 





8cabiaei) ' 



FIG. 547. Water mite (Trombidium fuliginosum), female chd. chelicene ; ptd. pedipalpi. 



(After Leuckart.) 



chelate. The legs vary somewhat in shape in the different groups, 

 according as they are used for prehension, for creeping, for running, 



