Xll] CLASSIFICATION 281 



Order 2. Diplopoda. [Progoneata.] 



Cylindrical Myriapoda with the bases of legs close together: 

 to each terguin behind the fourth correspond two pairs of legs : 

 no poison claws : genital opening on the third segment behind 

 the head. 



Ex. lulus. 



Sub-class C. INSECTA. 



Antennata with the body divided into three regions, head, 

 thorax and abdomen. Head bears the antennae and three pairs 

 of persistent mouth parts ; thorax three pairs of walking appendages 

 and usually two pairs of wings ; abdomen as a rule without ap- 

 pendages, genital opening on one of the posterior segments of the 

 abdomen. 



Order 1. Aptera. 



Wingless insects with hairy and scaly bodies ending in 

 anal filaments. No metamorphosis. 



Ex. Lepisma. 

 Order 2. Orthoptera. 



Jaws biting, fore- and hind-wings usually unlike. Meta- 

 morphosis incomplete. 



Ex. Forficula, Stylopyga, Phasma, Acridium, Gryllus. 

 Order 3. Paraneuroptera. 



Jaws biting. Wings alike, membranous, with many 

 nervures. Metamorphosis incomplete. Larvae aquatic with 

 rectal respiration. 



Ex. Aeschna. 

 Order 4. Ephemeroptera. 



Jaws vestigial in adult. Wings alike, membranous, with 

 many nervures. Metamorphosis incomplete. Larvae aquatic, 

 breathing by tracheal gills. 



Ex. Ephemera. 

 Order 5. Isoptera. 



Jaws biting. Wings alike, membranous, with many 

 nervures. Metamorphosis incomplete. Larvae subterranean. 

 A social system with castes of workers arid soldiers. 



Ex. Calotermes, Eutermes. 



