624 
Mr. J. O. Westwood on the Paussida , 
base of the part which Afzelius terms the gula triangularis,— to 
consider that part, which Latreille has not noticed, as the 
representative of the mentum, and consequently, the “ dents 
laterales” of Latreille, or the external palpi of Afzelius, as the 
produced anterior angles of the mentum ; 1st, from the evident 
analogy between it and the mentum of Pentaplatarthrus and 
Platyrliopalus ; 2ndly, because Latreille himself has shown 
that the mentum is not always articulated at the base, as in 
Siagona, which he describes in the Genera Crustaceonnn, $c. 
vol. iv. p. ii08. as “ suturd nulla bnsilari et processu paginae 
infer a3 capitis efformatum 3rdly, because the labial palpi 
arise between it and the true lip, which appears to be the 
true typical structure of the Coleoptera ; and 4thly, because the 
maxillae arise at the outer sides of the produced spines and 
within the mouth j in which respect this formation also agrees 
with the typical structure of the Coleoptera , where the base of 
the maxillae arises at the outer sides of the mentum ; whereas 
in Catogenus, Passandra , Megagnathus, $c. the maxillae arise 
within or between the produced lobes or spines. 
As to the “ dent intermediate” of the labium mentioned by 
Latreille, it appears from the observations of Afzelius, that it is 
not a constant generic character ; its examination, however, in 
the various species is rendered more difficult in consequence of 
the peculiar arched formation of the maxillary palpi described 
by Latreille as above. 
The labial palpi are generally bent backwards, although, as 
may be observed from Afzelius s figures, they are occasionally 
stretched forward ; in which latter case they fill up the space 
formed by the arch of the maxillary palpi, and almost entirely 
conceal the lip. 
The paucity of joints in the antennae, and their comparatively 
immense size, are circumstances well worthy the attention of 
the 
