218 INSECTS. 



space between these, being placed, the one above the upper pair, 

 and the other under the lower. In insects which feed on solid 

 substances, the four lateral pieces are considered as jaws, and the 

 other two pieces as lips. The two upper jaws, generally horny 

 or scaly, similar to strong teeth, and without an articulated ap- 

 pendage, have been distinguished by Fabricius under the name 

 of mandibles, (mandibulce,) the two lower only preserving the 

 name of jaws, (maxillae.) On the back of these are one or two 

 jointed filaments, called antennulce, but oftener palpi a cha- 

 racter which distinguishes them from the mandibles. They are 

 generally narrow, elongated, compressed, horny, or scaly till 

 near the origin of the palpi, with the upper extremity membra- 

 nous or coriaceous, in the form of a reversed triangle, ciliated or 

 hairy, and accompanied often on the internal side by a smaller 

 piece, named the internal lobe or division. The part or lobe 

 forming the upper extremity of the jaw sometimes appears 

 in the form of a small palpus of two joints, which is termed the 

 internal maxillary palpus ; in others it forms a vesicular, nak- 

 ed, vaulted appendage, called by Fabricius, from its form, ga- 

 lea. In both these cases the extremity of the jaw, or the por- 

 tion covered by the internal palpus or galea, is always horny, 

 pointed, in the form of a hook or tooth, or armed with denta- 

 tions or spines. These insects are always carnivorous or gnaw- 

 ers. When the jaws have neither internal palpus or galea, 

 are entirely horny, and armed with teeth, the insects may be 

 considered as very voracious. The number of the exterior 

 maxillary palpi varies from two to six. The two pieces oppo- 

 site to these lateral parts have been termed lips ; the upper one 

 being generally termed the labrum, (labium superius.) The 

 under one, termed the labium, or labium infer ius, is formed of 

 two parts ; one inferior, generally horny or coriaceous, is the 

 chin, (mentum,) the other membranous, sometimes entire, some- 

 times notched, or trifid, and bearing the palpi, is termed ligula. 

 These palpi have from two to four joints, and are called labial. 

 They are generally shorter than the exterior maxillary palpi. 

 The pharynx is situate between the jaws and the lip. The 

 interior of the mouth in the Orthoptera and some other insects 

 has a fleshy caruncle in the form of a tongue or epiglottis. In 

 the Hymenoptera the pharynx is formed by a triangular pro- 

 cess, named epipharynx or epiglossus by Savigny. In this or- 



