. MYRIAPODA 65 



legs on each segment; also, on the head, a pair of antennae, 

 a pair of mandibles, and one pair of maxillae. Millipeds 

 are usually cylindrical in form, but some species are flat. 

 They are slow-moving sluggish creatures whose food con- 

 sists entirely of vegetation. They often do damage to 

 crops or greenhouse plants. Julus and Polydesmus are 

 common genera. 



Order. 2. Chilopoda. This order includes the centi- 

 pedes, which have only one pair of legs on each metamere. 

 The body is flat and has maxillipeds, which are a pair of 

 modified legs, in addition to the antennae, mandibles, and 

 maxillae mentioned as occurring in the last order. The 



Heart Malpighian tubule 



Optic gangl,on nteron 

 Antenna /Brain 



35. A centipede with the body wall and appendages of the left side re- 

 moved to show the internal organs. Compare with Fig. 27. 



maxillipeds in centipeds are poison claws. They have 

 little openings at their tips which connect with poison 

 glands within the body. The poison claws are used in 

 killing small insects and spiders for food. The large 

 tropical centipedes inflict painful bites, and have even been 

 known to kill children. 



Order 3. Symphyla. These are small myriapods with 

 only twelve pairs of legs. They are rare, but are of some 

 theoretical interest because they resemble the most primi- 

 tive insects (Aptera) in the structure of their mouth parts 

 and in some other features. 



Many of the myriapods remain with their eggs until they 

 hatch. Some species build little nests by hollowing out a 

 space in the ground or in a rotten log, or by plastering little 

 pellets of mud together to make a dome-shaped case. 



