COLEOPTEROUS INSECTS. 101 



ilrefy concealed within the cavity of the mouth, 

 while in others they are nearly equal to half the 

 'ength of the body. Instances of the latter may be 

 seen in several of the species figured, particularly 

 Prionus cervicornis (Plate XXIIL), Chiasognathus 

 Chiloensis (Plate XVIII.), and the stag-beetle. 



The under jaws (maxilla) are likewise two pro- 

 jecting pieces, inserted on each side of the moutn, 

 immediately below the mandibles. As in the last- 

 named organs, their action is horizontal, but their 

 texture is generally less rigid, their colour usually 

 paler, and their internal edges ciliated or fringed 

 with hairs. The tip is frequently acute, and in one 

 beautiful tribe of beetles (Cicindelidci) it terminates 

 in a moveable claw ; but in many instances the 

 maxillae are lobed, and of a spongy consistence at 

 the extremity. As accessory to the mandibles, they 

 are employed in holding the food, lacerating it, and 

 subjecting it to a still further comminution, after 

 the harder parts have been broken down by the 

 more powerful action of the upper jaws. 



Towards the middle of the outer edge of the 

 maxillae, there emerge two slender filiform processes, 

 composed of several joints, named palpi. These 

 are usually termed maxillary palpi, to distinguish 

 them from another pair which take their origin in 

 the under lip. In many beetles each jaw is fur- 

 nished with two of these appendages, in which case 

 they are distinguished from each other as the ex- 

 ternal and internal palpi j but in numerous Instances 



