230 Mr. West wood 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) Trogosita as the type of a 

 group of genera, (although we may perhaps doubt its affinity with many 

 other of his XylophagiJ 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. Monotonia, J^emosoma, 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 maxillee of 

 this genus (which is admirably figured, with its dissections, by Sturm, in his 

 Deutchsland's Fauna) furnished with two processes, as in Cuctyw5, 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. xlvii. fig. 4.) which 

 is evidently a modification of the formation of the same parts in Caiogenus 

 and Passandra. The last three joints of the anten,n<B of Megagnathus 

 are rather larger than the others. 



Trogosita, 



as at present constituted, (like Cucujus^) comprises several distinct forma- 

 tions. Thus, in Tr. Carahoides, the joints of the antenncB gradually in- 

 crease in size to the tips ; the mandibles are trigonate and notched at the 

 apex, the maxilleB are furnished with a single process,f the labium is 

 nearly quadrate, and with the front margin entire. I have already no-r 



* See Note D. 



f I say a single process, because the inner one appears to be only rudimen- 

 tal, " Basilari et interne saltern minimo, vix distinguendo, non prominulo," 

 Latr. Gen. Cr. &c,, Vol. Ill, p. 22, Note. 



