270 



CLASSIFICATION OF ANIMALS 



577. Class 9. Apterygogenea. This class is often grouped 

 with the insects as the lowest order. They have many char- 

 acters in common with insects and are doubtless closely related. 



FIG. 1 60. Mouth parts of a cockroach, Ischnoptera pennsylvanica. A, 

 labrum; B, mandible; C, hypopharynx; D, maxilla; E, labium; c, cardo; g (of 

 maxilla) galea; g (of labium) glossa; /, lacinia; Ip. labial palpus; m, mentum; 

 mp, maxillary palpus; p, paraglossa; pf, palpifer; pg, palpiger; s, stipes; sm, 

 submentum. B, D and E are in ventral aspect. (From Folsom.) 



FIG. 161. Alimentary tract of a grasshopper, Melanoplus. c, Colon; cr, crop; 

 gc, gastric caeca; i, ileum; m, midintestine, or stomach; ml, malpighian tubules; 

 o, oesophagus; />, pharynx; r, rectum; s, salivary gland. (From Folsom.) 



There is a distinct head, a thorax of three segments and ai 

 abdomen of 6-1 1 segments. The head bears a pair of antennae 



