318 



Melanterius and Dietliusa lies in tlie second abdominal seg- 

 ment, and that segment cannot be used for the two species now 

 under consideration ; and as the clothing is so dense that the 

 derm is partly hidden, it appears desirable to regard them 

 both as belonging to Diethum. 



DiETHUSA. 



This genus is unsatisfactorily close to Melanterius. Never- 

 theless, as each is now known to contain man}?- species { Diethusa 

 24, Melanterius 45 ; numbers that will probably be more than 

 doubled), most of which are easily referable to one or the other, 

 it appears desirable to maintain them. The principal features^ 

 relied upon to distinguish them are the grooving of the femora 

 and the size of the second abdominal segment. Owing to the 

 clothing, however, it is often difficult to decide as to whether 

 a femur is grooved or not. The size of the second segment, 

 however, is readily seen, but this is a character that sometimes 

 must be treated in an arbitrary manner, and in two species at 

 least (Diethusa am'plicornis and M elanterius amplipennisj is 

 sexually very different. On the whole, however, it appears 

 desirable to refer all the wide, densely-clothed species with the 

 second segment short to Diethusa. In all the species that have 

 been referred to that genus the clothing is dense, and in the 

 majority of species now standing under Melanterius it is much 

 less dense, sometimes almost absent, at anyrate on the pro- 

 notum, where each puncture contains but one scale ; that 

 usually is depressed below the general level. There are, how- 

 ever, three exceptions to this, viz., floricliis, congruus, and 

 am'pli'pennis, all of which are commented upon. The peculiar 

 armature of the four front tibiae of some species of Diethusa 

 is not a generic feature ; in the females of some species the 

 spur, or tooth, commences at the extreme upper end of the 

 dilated apex of the tibiae, and slightly diverges from the oblique' 

 apex : in others it commences half-way down, but in the 

 majority it is terminal, as in the males. 



Diethusa apicalis, n. sp. 



Reddish-castaneous ; prothorax in parts somewhat infus- 

 cate. Densely clothed with stiff scales, varying from 

 stramineous to ochreous, but uniformly pale on under-surf ace ; 

 elytra with a few feeble sooty spots. 



Rostrum long, thin, and almost parallel-sided: with an 

 impunctate median line from base to apex, with punctures in 

 rows behind antennas. Scape inserted in middle of rostrum, 

 distinctly shorter than funicle; first joint of funicle slightly 

 shorter than second. Prothorax rather lightly transverse;. 



