<§> 295. THE ARACHNOID. AE. 365 



ORDER 11. 



Cephalothorax unarticulated, or biarticulated. Respiratory organs con- 

 sisting of tracheae. 



SUB-ORDER in. ACARINA. 



Abdomen unarticulated and fused with the cephalothorax. Palpi simple. 



Family : Acarea. 



Genera : Demodex, Sarcoptes, Glycyphagus, Tyroglyphus, Melichares, 

 Dermaleichus, Acarus, Pteroptus. 



Family : Hydrachnea. 



Genera : Limnochares, Arrenurus, Eyla'is, Diplodontus, Hydrachna, Atax. 



Family : Oribatea. 



Genera : Hoplophora, Oribates, Zetes, Pelops, Damaeics. 



Family: Gamasea. 



Genera : Dermanyssus, Uropoda, Gamasus, Argas. 



Family : Ixodea. 



Genus: Ixodes. 



Family: Bdellea. 



Genera : Bdella, Molgtis. 



Family : Trombidina, 



Genera : Erythraeus, Trombidium, Smaridia, Tetranychus, Rhyncholo' 

 phus, Rhaphygnathus, Pentkaleus. 



SUB-ORDER IV. OPILIONINA. 



Abdomen articulated, but indistinctly separated from the cephalothorax. 

 Palpi simple. 



Genera : Pkcdangium, Gonyleptes, Eusarcus. 



SUB-ORDER V. PSEUDOSCORPII. 



Abdomen articulated, but indistinctly separated from the cephalothorax. 

 Palpi forficulate. 



Genera : Obisium, Chelifer. 



SUB-ORDER VI. SOLPUGIDAE. 



Abdomen articulated, distinctly separated from the cephalothorax. 

 Palpi simple. 



Genus : Galeodes. 



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