160 EVE2SriNGS AT THE MICKOSCOPE. 



CHAPTER IX. 



INSECTS : THEIE MOUTHS. 



The parts of the mouth in different insects afford an 

 almost endless store of delightful observations ; and the 

 more as, with all their variety, they are found to be in 

 every case composed of the same essential elements. 

 You would not think so, indeed ; you would naturally 

 suppose — ^looking at the biting jaws of a Beetle, the 

 piercing proboscis of a Bug, the long elegantly-coiled 

 sucker of a Butterfly, the licking tongue of a Bee, the 

 cutting lancets of a Horse-fly, and the stinging tube of 

 a Gnat — ^that each of these organs was composed on a 

 plan of its own, and that no common structure could 

 exist in instniments so diverse. But it is so, as we 

 shall see. 



We may consider the various organs of the mouth 

 as njost harmoniously and perfectly developed in the 

 active carnivorous Beetles, the Carabidce, or ground- 

 beetles, for instance. Let us examine the head of 

 this black Scarites, from the garden ; and first from 

 above. 



In front of the polished head-shield, and jointed to it 

 by a broad transverse straight edge, is a four-sided 

 piece, forming an oblong square, nearly twice as broad 

 as long, a little convex, and marked with six little pits 



