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 dernikre piece” (the “levre inferieure”) “est 
petite, cornee, presque carree, un peu voutee, tridentee au bord 
superieur, clont le milieu est un peu plus eleve ; les dents late- 
rales sont formees par les saillies des angles lateraux ; le milieu 
de la face anterieure de cette levre est en carcne et se prolonge 
en pointe au sommet, d’oh resulte la dent intermediate.” 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. 
Lor 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 pair 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, Fassandra , Me- 
gagnathus , #c. 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 
4 l base 
VOL. XVI. 
