§ 295. THE ARACHNOIDAE. 365 



ORDER IL 



Cephalothorax unarticulated, or biarticulated. Respiratory organs coa- 

 eisting of tracheae. 



SUB-ORDER III. ACARINA. 



Abdomen unarticulated and fused with the cephalothorax. Palpi simple. 



Family: Acarea. 



Genera : Demodex, Sarcoptes, Glycyphagus, Tyroglyphus, Melichare^, 

 Dermaleichns , Acarus, Pteroptus. 



Family : Hydrachnea. 



Genera : Limnockares, Arrenurus, Eyldis, Diplodontus, Hydrackna, Atax^ 



Family : Oribatea. 



Genera : Hoplophora, Oribates, Zetes, Pelops, Damaeus^ 



Family : Gamasea. 



» Genera : Dermanyssus, Uropoda, Gamasus, Ar gas. 



Family: Ixodea. 



Genus : Ixodes. 



Family : Bdellea, 



Genera : Bdella, Molgus. 



Family : Tkombidina. 



Genera : Erythraeus, Troinbidmm, Smaridia, Tetranyckiis, RhynchcHo- 

 phus, Rhaphygnathus, Penthaleus. 



SUB-ORDER IV. OFILIONINA. 



Abdomen articulated, but indistinctly separated from the cephalothorax. 

 Palpi simple. 



Genera : Phcdangmm, Gonyleptes, Eusarciis. 



SUB-ORDER V. PSEUDOSCORPII. 



Abdomen articulated, but indistinctly separated from the cephalothorax. 

 Palpi forficulate. 



Genera : Obisium, Chelifer. 



SUB-ORDER TT. SOLPUGIDAE. 



Abdomen articulated, distinctly separated from the cephalothorax. 

 Palpi simple. 



Genus : Galeodes. 

 31* 



