CLASSIFICATION OF ARTHROPODA. 231 



Autaraclinae {continued.), 



Linguatulina. 



Pentastomum. 



PseudaraclinaB*). 



Tardigrada. 



Macrobiotus. 



Pycnogonida. 



Fycnogonum, Nymphon. 



II. Myriapoda. 



Cliilopodn. 



Scolopcndra, Lithobins. 

 Chilognatha. 



Polydesmus, Julus, Glomeris. 



III. Insecta (Hexapoda). 



1. Aptera-f). 



Collembola. 



Symnthurus, Podura. 



Thysanura. 



Campodea, Lepisma, Macbilis. 



2. Pterygota. 



Pseudoneuroptera. 

 Amphibiotica. 



Ephemera, Chloe, Perla, Libellula, Agrion, ^Eschna. 

 Corrodentia. 



Psocina. 



Psocus, Troctes. 

 Embida. 



Enibia. 



Thysanopoda. 

 Tkrips. 



Termitida. 

 Termes. 

 Neuroptera. 



Planipennia. 



Panorpina. 



Panorpa, Billacns. 

 Sialida. 



Rhaphidia, Sialis. 

 Hemerobida. 



Heraerobius, Chrysopa, Myroieleon. 

 Trichoptera. 



Phryganida. 



Phryganea, Limnopliilns. 

 Strepsiptera. 



Stylops, Xenos. 



* Very divergent forms are found in both divisions of the Pseudarachna?, and 

 have really very little in common except their divergence from the Autarachna?. It is 

 not quite certain that the Tardigrada have any relations to the Tracheata. 



f The two groups united in the division of the Aptera are removed from all 

 other Insects, owing, to the difference in their organisation ; we cannot therefore place 

 them with any one order. Though they have much in common with the Pseudo- 

 neuroptera, it is because the latter are so low. Their want of wings must be re- 

 garded as a primitive condition, as compared with the adaptative wingless condition, 

 examples of which may be seen in nearly all orders of the Pterygota. 



