ARACHNOIDEA 



267 



571. Order 8. — The Acarina are the mites and ticks. Many of the 

 members of this group are parasites. The body cannot be divided into 

 cephalo-thorax and abdomen as all evidence of segmentation is lacking. 

 The mouth parts are often adapted for piercing and sucking. The legs 



Fig. 155.— 



■'^►^ 



The home of the trap-door spider laid open 



with a pin. X 3/4. 



The door is held open 



are often merely hold-fast organs. The parasitic forms are often much 

 degenerate. 



572. Order 9. — The Linguatulida are parasitic forms especially notable 



