INSECTA. 55 



bium), and these two pieces more or less completely conceal the 

 proper jaws, which are lodged between them. 



The upper pair of jaws (mandibulfs) are two hard and powerful 

 hooks (c), placed immediately beneath the upper lip, and so ar- 

 ticulated with the cheeks that they move horizontally, opening and 

 shutting like the blades of a pair of scissors. Their concave edge 

 is armed with strong denticulations of various kinds, sometimes fur- 

 nished with cutting edges, that, like sharp shears will clip and di- 

 vide the hardest animal and vegetable substances ; sometimes they 

 form sharp and pointed fangs, adapted to seize and pierce their 

 victims ; and not unfrequently they constitute a series of grinding 

 surfaces, disposed, like the molar teeth of quadrupeds, to triturate 

 and bruise the materials used as food. The variety of uses to which 

 these mandibles can be turned is indeed amazing. In the car- 

 nivorous beetles, their hooked points, more formidable than the 

 teeth of the tiger, penetrate with ease the mailed covering of their 

 stoutest congeners ; and in the dragon-fly they are scarcely less 

 formidable weapons of destruction. In the locust tribes these 

 organs are equally efficient agents in cutting and masticating leaves 

 and vegetable matters adapted to their appetites ; while in the 

 wasps and bees they form the instruments with which these insects 

 build their admirable edifices, and, to use the words of a popular 

 author, supply the place of trowels, spades, pick-axes, saws, scissors, 

 and knives, as the necessity of the case may require. 



Beneath the mandibles is situated another pair of jaws, of similar 

 construction, but generally smaller and less powerful; these are 

 called the maxilla (F). 



The lower lip, or labium (E), which closes the mouth inferiorly, 

 consists of two distinct portions, usually described as separate 

 organs, the chin (mentum), that really forms the inferior border of 

 the mouth ; and a membranaceous or somewhat fleshy organ, repos- 

 ing upon the chin internally, and called the tongue (lingua) of the 

 insect (D). 



All these parts enter into the composition of the perfect mouth 

 of an insect, and, from the numerous varieties that occur in their 

 shape and proportions, they become important guides to the ento- 

 mologist in the determination and distribution of species. For 

 more minute details concerning them, the reader is necessarily re- 

 ferred to authors who have devoted their attention specially to this 

 subject ; we must not, however, omit to mention certain appen- 

 dages or auxiliary instruments inserted upon the maxilla and the 

 labium, usually named the palpi, or feelers, and most probably 



