230 Mr. Westwood on the Affinities of Clinidium. 
yet that author has always regarded Trogosita as forming, with other ge~ 
nera, a portion of his artificial group Xylophagi ; indeed, of the pro- 
priety of, at least, considering (with Latreille) Trogostta as the type of a 
group of genera, (although we may perhaps doubt its affinity with many 
other of his Xylophagi,) the student will be at once convinced, on com- 
paring the figures of the trophi of Trogosita and Megagnathus given by 
Sturm, and Mr. Curtis’s dissections of Cicones and Bitoma ; to which lat- 
ter genera I may add, from actual dissection, Synchita, Cerylon, Rhyzo- 
phagus, Monotoma, Nemosoma, and probably Lyctus.* 
’ Perhaps the singular genus 
MEGAGNATHUS 
ought to be considered as the stepping-stone between the two families, 
since in many important respects it appears to be allied to the insect con- 
sidered above as the Cucujus unifasciatus ; and we find the mawille of 
this genus (which is admirably figured, with its dissections, by Sturm, in his 
Deutchsland’s Fauna) furnished with two processes,as in Cucujus,although 
the interior one is not unguiform as in some of the species of that genus. 
The parts of the mouth are, however, considerably more elongated. There 
is a portion of the structure of this insect, which it is somewhat singular 
Sturm should have omitted to figure, namely, the extraordinary prolonga- 
tion of the under sides of the head, (Tab. Supp. xvi. fig. 4.) which 
is evidently a modification of the formation of the same parts in Catogenus 
and Passandra. The last three joints of the antenne of Megagnathus 
are rather larger than the others. 
TROGOSITA, 
as at present constituted, (like Cucujus,) comprises several distinct forma- 
tions. Thus, in Tr. Caraboides, the joints of the antenne gradually in- 
crease in size to the tips ; the mandibles are trigonate and notched at the 
apex, the mawille are furnished with a single process,t the labium is 
nearly quadrate, and with the front margin entire. I haye already no- 
* See Note D. 
+ I say a single process, because the inner one appears to be only rudimen- 
tal, “ Basilari et interno saltem minimo, vix distinguendo, non prominulo,” 
Latr. Gen. Cr, &e., Vol. III. p, 22, Note. 
