Jaws 



15 



found in the second pair, though these parts are smaller 

 and simpler. The basal segments {cardines) are fused 

 together, forming a broad plate or flap {submentum) 

 (fig. 12 sm) which hangs below the back region of 

 the head, behind the mouth. To this the stipites are 

 attached, their bases joined together to form a smaller 

 plate {tnentum) (fig. 12 w) and their separated distal 

 portions each carrying its hood (fig. 1 2 pg) and blade. 

 The three segmented 

 palp (fig. 12 pd) is 

 borne on a process 

 (^palpiger) situated out- 

 wardly at the base of 

 the stipes. The pair 

 of jaws thus made up 

 is the second pair of 

 maxilU. But because 

 of the fusion of the 

 basal parts of these 

 jaws to form an un- 

 paired plate, and their 

 position behind the 

 mouth (or, in insects 

 whose head is carried 

 horizontally, below 

 the mouth), most 

 entomologists call 

 them the lower lip 

 {labium) ?- 



On the inner (front) 

 side of this pair of jaws is situated a fold in the skin of 

 the mouth known as the tongue {lingua or hypopkarynx). 

 On the hinder surface of the tongue opens the duct of 

 the spittle-glands (l). 



In the more highly developed insects, the fusion of 

 ^ The hoods {gaUie) of these jaws are often known as xh^paraglossa. 



Fig. 12. — Cockroach's Head from behind 

 showing maxillae. Magnified lo times. 

 ca. cardo ; st. stipes ; ga. galea ; la. 

 lacinia ; pa. palp, of ist ma.\illae ; sm. 

 submentum ; m. mentum; pg- galea ; pa. 

 palp, of 2nd maxillae. From Miall & 

 Denny. 



