74 ANIMAL BIOLOGY 



pair of biting jaws (mandibles, ok), (3) a pair of grasp- 

 ing jaws (maxillae, A, B), and (4) a lower lip (labium, m,a, b). 

 The grasping jaws bear two pairs of 

 "' <?\"* jointed jaw fingers (maxillary palpi, 



D, C), and the lower lip bears a pair 

 $%&/ ° f similar 1J P nn S crs (labial palpi, d). 

 f i r ^L|\ ^he biting jaws move sideways ; they 



vV''--v*-^l!k usually have several pointed notches 

 which serve as teeth. Why should the 

 grasping jaws be beneath the chewing 



fig. 123.- MoriH j aws ? why is it better for the lower 

 Parts of Beetle. . . 



lip to have fingers than the upper lip ? 



Why are the fingers (or palpi) 



jointed ? (Watch a grasshopper 



or beetle eating.) Why does an 



insect need grasping jaws ? 



The chest, or thorax, consists 



of three rings (Fig. 124) called 



the front thorax (prothorax), 



middle thorax (mesothorax) and 



hind thorax (metathorax), or 



first, second, and third rings. W 



The first ring Fig. 124. — External Parts 



Jib. / u 4.1 c of a Beetle. 



fj bears the first 



pair of legs, the second ring bears the 



second pair of legs and the upper or front 



wings, and the third ring bears the third 



pair of legs and the under or hind wings. 



The six feet of insects are characteristic 



Fig. 125. — leg f them, since no other animals have that 

 of Insect. 



number, the spider having eight, the craw- 

 fish and crabs having ten, the centipedes still more, while 

 the birds and beasts have less than six. Hence the insects 



