468 



LECTURE XIX. 



a. acarina. 



Hydra chnidm. 



Oribattdx. 

 Gamasidm. 



IXODIBM. 



Bdellidm. 

 Trombididm. 



B. Opilionina. 



Levigrada. Legs much developed ; abdomen rudimentary : 



bisexual. 

 Genera Pycnogonum, Nymphon, Ammofhea, Pal- 

 lene, Phoxichilus. 



Order Trachearia. 



Respiratory organs consisting of trachese. Ceplialothorax one or 

 two articulated. Bisexual. 



Abdomen unarticulated and fused with the cepha- 



lothorax. Palpi simple. 

 Genera Sarcoptes, Glycyphagus, Tyroglyphus, 



Melichares, Acarus, Pteroptus. 

 Genera Limnochares, Arrenuriis, Diplodontus, 



Hydrachna, Atax. 

 Genera Hoplophora, Oribates, Pelops, DamcBUs. 

 Genera Dermanyssus, Uropoda, Gamasus, Ai-gtis. 

 Genus Ixodes. 

 Genera Bdella, Molgus. 

 Genera Erythraus, Trombidium, Smaridia, Te- 



tranyclius, Rhyncholophus, Penthaleus. 

 Abdomen articulated, but indistinctly separated 



from the cephalothorax. Palpi simple. 

 Genera Phalangium, Gonyleptes, Eusarcus. 



C. PsEUDOSCORPn. Abdomen articulated, but indistinctly separated 



from the cephalothorax. Palpi forficulate. 

 Genera Obisium, Chelifer. 



D. SoLPUGii. Abdomen articulated, distinctly separated from 



the cephalothorax. Palpi simple. 

 Genus Galeodes. 



Order Pulmotrachearta. 



Respiratory organs consisting of trachea and pulmonary sacs. Ab- 

 domen and cephalothorax unarticulated, distinct from each other. 

 Nat ANTES. Genus Argyroneta. 



Sedentes. Genera Tkeridion, Episina, Linyphia, Zosis, Ulo- 



bortis, Tetragnatha, Epeira, Nyssus, Agelena, 



Lachesis, Tegenaria. 

 Errantes. Genera Artema, Pholcus, Latrodictiis, Clofho, 



Drassus, Clubiona. 

 Vagantes. Genera Clastes, Spa7-assits, Philodromus, Ei'ipns, 



Selenops, Thomisus, Delena. 

 Venantes. Genera Attus, Myrmecia, Dolophenes, Sphasus, 



Ctenus, Dolomedes, Lycosa, Omosites, Seges- 



