312 INSECTA. 



armed with strong denticulations of various kinds, sometimes furnished 

 with cutting edges that, like sharp shears, will clip and divide the 

 hardest animal and vegetable substances ; sometimes they form sharp and 

 pointed fangs, adapted to seize and pierce their victims ; and not unfre- 

 quently they constitute a series of grinding surfaces, so disposed (like the 

 molar teeth of quadrupeds) as 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 carnivorous 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, pickaxes, saws, scissors, and knives, as the 

 necessity of the case may require. 



(820.) Beneath the mandibles is situated another pair of jaws, of 

 similar construction, but generally smaller and less powerful ; these are 

 called the maxillce (fig. 155, F). 



(821.) The lower lip, or labium (fig. 155, 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 membranous or somewhat fleshy organ, 

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

 insect (D). 



(822.) 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 entomologist in 

 the determination and distribution of species. For more minute details 

 concerning them, the reader is necessarily referred to authors who have 

 devoted their attention specially to this subject ; we must not, however, 

 omit to mention certain appendages or auxiliary instruments inserted 

 upon the maxillce and the labium, usually named the palpi, or feelers, 

 and most probably constituting special organs of touch, adapted to faci- 

 litate the apprehension and to examine the nature of the food. The 

 maxillary feelers (palpi maxillares) are attached to the external margin 

 of the maxillaB by the intervention of a small scale and very pliant 

 hinge, and consist of several (sometimes six) distinct but extremely 

 minute pieces articulated with each other. The labial feelers (palpi 

 labiales) are inserted into the labium close to the tongue, or occasionally 

 upon the chin (mentum) itself. The joints in the labial palpi are gene- 

 rally fewer than in the maxillary, but in other respects their structure 

 and office appear to be the same. 



(823.) In the suctorial orders of insects we have the mouth adapted 



