S5G EXTERNAL ANATOMY OF INSECTS. 



where it is jointed ; in other cases its base. It is 

 usually seated between the base of the Maxil- 

 la*. 



b Palpi Labiales (the Labial Feelers). Two jointed 

 sensiferous organs, the use of which is not clearly 

 ascertained, which emerge, one on each side, from 

 the Labium, mostly near its summit b . 



C Mandibul^: (the Uppe7-jaws). Two transverse late- 

 ral organs, in most insects used for manducation ; 

 generally corneous, moving horizontally, and clos- 

 ing the mouth above, under the Labium c . They 

 include the Prostheca, Dentes, and Mola. 



a Prostheca (the Prostheca). A subcartilaginous pro- 

 cess attached to the inner side, near the base, of the 

 Mandibular of some Staphyli?iidce d . Ex. Ocypus 

 similis K., Creophilus maxillosus K., &c. 



b Dentes (the Teeth). The terminating points of the 

 Mandibida?. They include the Incisores, Laniarii, 

 and Molares e . 



A Incisores (the Cutting-teeth). Teeth somewhat 

 wedge-shaped, externally convex and internally 



3 Plates VI. and VII. a", and XXVI. Fig. 34, 35. 



The part in this work regarded as the mentum, does not in all 

 cases accord with what MM. Latreille, Savigny, &c. have regarded 

 as entitled to that denomination. Thus in Hymenopiera, their 

 Mentum is what we term the Labium, while our Mentum is the 

 small piece upon which that part sits (Plate VII. Fig. 3. a"). This 

 is called the Fulcrum in Mon. Ap. Angl. (See i. Explan. of the 

 Plates.) Our Mentum may generally be known by its situation be- 

 tween the hinges and base of the Maxillae. 



b Plates VI., VII., and XXVI. b". c Ibid. 



d Plate XIII. Fig. 7. c". 



e Marcel de Serres Comparaison des Organes de la Mastication de& 

 Orthopteres. 7- Ann. du Mus. 11. 



