462 Coleojjterological Notices, IV. 



in classification, and, assuming the definition and scope of certain 

 genera as known to this author, such as the Schonherrian Baridius 

 and Centrinus, there can be no doubt that he was entirely justified 

 in coming to the conclusion expressed in the foot-note on page 3, 

 vol. VII, of the "Genera." Whatever opinion may be held, how- 

 ever, concerning the usefulness of mandibular modifications for the 

 purposes to which they are here applied, it can only be said that I 

 have found the' generic groups defined by them to be quite homo- 

 geneous within themselves in external appearance and distinctly 

 separated from each other in general habitus, and these facts admit- 

 tedly constitute one of the best tests of generic validity. In addi- 

 tion we are enabled in this way to really define and fix some tangible 

 limits to the genus Centrinus, which has never been accomplished 

 by any other means. The fact that the prosternal sulcus and de- 

 gree of separation of the anterior cox« prove to be of uncertain 

 value for generic definition in Centrinus and its immediate allies, 

 because of the marked sexual divergencies in the conformation of 

 these ])arts in many species, taken in connection with the intro- 

 generic homogeneity of facies of the groups defined by mandibular 

 structure, prompts me to believe that we have here, at least, a prac- 

 tical solution of one of the most perj)lexing problems of the Cur- 

 culionida;. 



The prosternum is subject to almost every possible modification ; 

 it may be either perfectly flat or variously foveate or longitudinally 

 sulcate to a greater or less degree. The sulcus when present does not 

 generally receive the beak in repose, but there are at least three 

 genera — Coleomerus, Diorymerus and Aulobaris — in which the beak 

 can be placed in the groove just as in any normal cryptorhynch, and, 

 in Coleomerus, the groove often extends posteriorly far into the meta- 

 sternura ; in the other two genera, however, it does not pass beyond 

 the prosternum. The apical margin is usually entire, but frequently 

 sinuate in the middle, and, at a short distance behind the apex, there 

 is a more or less distinct transverse constriction. The degenerative 

 remnants and modifications of the transverse constriction and longi- 

 tudinal sulcus or of a combination of the two, frequently give rise 

 to subapical foveae of various forms, sometimes continued posteri- 

 orly by folds of the surface.' The anterior cox* are of every 



1 In some genera the two subapical fovese serve as receptacles for the robust 

 basal joint of the antennal funicle, when the beak is placed closely against 

 the body, these portions of the sulcus or constriction being therefore preserved 

 for a useful purpose. 



