140 EVENINGS AT THE MICROSCOPE. 



latter is the tongue, while the jointed organs on each side 

 are called feelers, — palpi ; though this is a begging of the 

 question, for we do not really know the function of these 

 organs. The chin, the tongue (ligula), and these palpi, 

 constitute together the under lip. 



Between the tongue and the biting jaws, or mandibles, 

 we see a pair of organs similar to these latter, but smaller, 

 less solid, and more curved. These are the under or 

 secondary jaws, maxilla, the use of which is to hold the 



MOTJTH OF BEETLE. 



{Seen from beneath.) 



u, upper lip ; 6, mandibles ; c, maxills ; d, maxillary palpi ; e, tongue * 



/, labial palpi ; g t chin. 



food, while the biting jaws work on it, and to convey it 

 when masticated to the back of the mouth. Their whole 

 inner edge is set with short stiff bristles, which towards 

 the tips of the jaws become spines. Near the bases of 

 these jaws, on the outer edge, are jointed two other pairs 

 of palpi, one pair to each jaw ; of which the exterior is 

 much stouter and longer than the interior. Thus this 



