MYRIAPODA 



269 



574. Class 7. Myriapoda. — The ''thousand legs" have a 

 worm-like body divided into similar segments, a distinct head 

 with one pair of antennae, usually one pair of maxillae and with 

 one or two pairs of appendages on each body segment. Respira- 

 tion is by tracheae and the stigmata are arranged segmentally. 



575. Order 3. — The Diplopoda are the 

 common "thousand legs." The body is 

 cylindrical or half-cylindrical and is 

 covered with a chitinous cuticula hardened 

 by deposits of carbonate of lime. All the 

 segments except a few of the most anterior 

 and the last one bear two pairs of ap- 

 pendages. The animals are vegetable 

 feeders and harmless. 



576. Order 4. — The Chilopoda bear some 

 resemblance to the preceding group but 



Fig. 158. — Spirobolus, a Diplopod. 

 (From Folsom.) 



Fig. 159. — Campodea, an example 

 of the class Apterygogenea. (From 

 Folsom.) 



the body is usually flattened and no segment bears more than one pair of 

 appendages. There is a pair of mandibles, two pairs of maxillae and one 

 pair maxillipeds. The maxillipeds belong to the first body segment. They 

 are stout claws and contain a poison gland. The centipede of the south 

 is an example of this order but a more familiar one is the long-legged 

 Cermatia often seen in our dwellings where it preys upon other insects. 



