166 EVENINGS AT THE MICROSCOPE 



about on the microscope), and united with it, there is a 

 sort of solid square pedestal, on which stand a pair of 

 jointed organs, and between them an oblong horny plate 

 rounded at the tip, where it bears two bristles. This lat- 

 ter 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 



MOUTH OP BEETLE (seen from beneath). 



a, upper lip; b, mandibles; c, maxillae; d, maxillary palpi; e t tongue; 

 /, labial palpi; g, chin. 



organs. The chin, the tongue (Ugula), 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 curve.d. These are the under or sec- 

 ondary jaws, maxillce, the use of which is to hold the 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 toward the tips 

 of the jaws become spines. Near the base of these jaws, 



