a Family of Coleopterous Insects. 623 



scribed as the produced lateral angles of the mentum, as part of 

 the labium, expressly stating in the latter work that there is no 

 mentum. His description of the lower lip in the former work is 

 as follows: "Cette dernifere piece" (the "levre inferieure") "est 

 petite, cornee, presque carree, un peu voutee, tridentee au bord 

 superieur, dont le milieu est un peu plus eleve ; les dents late- 

 rales sont form6es par les saillies des angles lateraux ; le milieu 

 de la face anterieure de cette 16vre est en car^ne et se prolonge 

 en pointe au sommet, d'oii resulte la dent intermediaire." I 

 shall, however, endeavour to prove that there is a mentum, and 

 that these " dents laterales" are in fact the produced angles of 

 that organ, and that they are perfectly distinct from the labium. 

 For this purpose it is necessary for me to state, that these pro- 

 duced angles or "saillies" are not articulated at the base, but 

 merely produced portions of the gula triangularis of Afzelius : 

 indeed that author expressly says, that these parts seem to have 

 neither joints nor motion, and to be of a very different structure 

 and substance from the true palpi labiales : hence, therefore, 

 they cannot be considered as parts of the labium, which, typi- 

 cally regarded, is a distinct organ arising below the insertion of 

 the palpi ; and consequently the supposition of Latreille, that 

 these spines are "formees par les saillies des angles lateraux" of 

 the labium, must be considered as incorrect. It may indeed per- 

 haps be contended that these produced lateral spines are repre- 

 sentatives of the produced undersides of the head or under- 

 cheeks particularly developed, as in Catogenus, Passandra, Me- 

 gagnathus, SfC. and consequently, that they do not form part of 

 the mentum, which must either be sought for in the more 

 advanced or in the internal parts of the mouth, or must be, as 

 Latreille states, wanting. I am induced, however, from the 

 abhorrence which Nature entertains of such anomalies, — not- 

 withstanding the absence of any articulation at the sides or 

 VOL. XVI. 4 L base 



