424 



GENERAL ZOOLOGY 



Example: Julus virgatus, a common millipede. 

 Order 2. Chilopoda. A flattened body with one pair of legs to a 

 segment. Two pairs of maxillae. The first pair of legs are 

 maxillipeds, provided with poison glands. Reproductive 

 openings are posterior. 



Example: Scolopendra morsitans, a common southern 

 centipede. 



Man 



.Max.— 



La-'' 



Fig. 247. — A, chewing type of mouth parts as found in grasshopper; B, 

 piercing-sucking type as found in female mosquito, g, galea; h, hypopharynx 

 (a tonguelike prolongation of the floor of the mouth, attached to the inside wall 

 of the labium); l, labrum; La, labium; Lac, lacinia; Man, mandible; Max, maxilla; 

 p, palp. (After Metcalf and Flint: Destructive and Useful Insects.) 



CLASS V. INSECTA. Insects. Insects are characterized by 

 three body divisions, head, thorax, and abdomen, and by three 

 pairs of legs. The head bears four pairs of appendages; 

 antennae, maxillae, mandibles, and lips or labia (labrum and 

 labium). The trunk is composed of three segments, prothorax, 

 mesothorax, and metathorax, each of which bears a pair of legs. 

 The mesothorax and metathorax may each bear in addition 

 a pair of wings. Respiration is carried on by means of a 

 tracheal system. Insects are dioecious and the reproductive 

 openings are at the end of the body. A metamorphosis in 

 development is common. 



