COLEOPTEROUS FAMILY PAUSSID.E. 
165 
time taken out the labium ofonly one species of this genus, of which 
the anterior margin was quite simple, I was induced to believe 
that ill describing the labium as 3-dentate, Latreille had mistaken 
the two spines at the anterior margin of the mentum or gula trian¬ 
gularis for part of the labium. Having, however, recently dis¬ 
sected P. microcephalus, which appears to have been the species 
which he dissected (as he gives it as his first example of the genus, 
having received it from Mr. MacLeay), I find that its labium 
accords with Latreille’s description. As to the part which I have 
regarded as the mentum (a part which Latreille states is wanting), 
it may be contended that the two porrected spines represent the 
produced undersides of the head, or imdercheeks peculiarly 
developed, as in Catogenus, Passandra and Megagnathus ; but 
as the true mentum is occasionally soldered to the head (as in 
Siagona), and as the maxillee arise at the outersides of the pro¬ 
duced spines (thus agreeing with the typical structure of the 
Coleoptera, where the base of the inaxillm arises at the outorside 
ol' the mentum), I have the less hesitation, especially after a com¬ 
parison of this part in this genus and in the preceding, in regarding 
the gula triangularis as the representative of the mentum. 
As regards the external sexual marks of distinction in this 
genus, I am only able to state, that, according to Afzelius, the 
female of P. sphcerocerus differs chiefly from tho male in liaving 
the labial palpi rather narrower, the produced lobes or spines of 
the mentum glaucous, tho maxillary palpi shorter, with the second 
joint narrower, the abdomen longer, and tho posterior femora 
slenderer. In some individuals, we find the extremity of the 
abdomen furnislied with two acute curved diverging spines, which, 
I believe, will ho found to be a sexual peculiarity. 
The species of this genus are much more numerous than those of 
any of the other genera. Some of them, possessing a subcontinuous 
prothorax, and a broad clava to the antennm, are closely allied to 
the Platyrhopali; whilst otliers, witli a bipartite prothorax, seem 
to approach Pentaplatarthrus, althougli the structure of tho palpi, 
luaxillm, See., of tho last-named genus (see pi. 58, fig. 2, details) 
materially differs from that of the true Paussi. 
Of the liabits of this genus we possess but little information ; 
sufficient, however, appears to be known to lead us to infer that 
tlie species are nocturnal in their habits, being often attracted by 
the light in houses after dark, and that, like Clavigor, Lomecliusa, 
