COLEOPTEROUS INSECTS. 
101 
llrefy 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 XXIII.), Chiasognathus 
Chiloensis (Plate XVIII.), and the stag-beetle. 
The under jaws ( maxilla ) are likewise two pro- 
jecting pieces, inserted on each side of the mouth, 
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 ( CicindelidcE ) it terminates 
in 76. 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; but in numerous instances 
