Coleopterological Notices, IV. 461 



The beak may be excessively short and stout or correspondingly 

 long and slender, arcuate or nearly straight or variously bent at 

 different parts of its extent, divided from the head by a transverse 

 constriction or not, and with the antennae inserted at every con- 

 ceivable point, from near the extreme apex as in the male of Cono- 

 proctus 4-pushdatus, to near the base as in Simocopis of Pascoe or 

 our own Plocamus. The scrobes obliquely and rapidly descending 

 or nearly horizontal, sometimes completely inferior, coalescent be- 

 neath toward base or remaining widely separated. 



The antennae are comparatively constant in structure, especially 

 the funicle, which is invariably seven-jointed, with the basal joint, 

 and more rarely also the second, elongate to a greater or less degree, 

 the first sometimes as long as the entire remainder as in Barinus; 

 the second joint is, however, almost always at least somewhat longer 

 than the third. The club is modified to a very noticeable extent, 

 but it is seldom that these variations of structure can be employed 

 in differentiating the genera ; it may be very small or conspicuously 

 longer than the entire funicle as in Orthoris, and its basal joint may 

 constitute from two-thirds of the whole to very much less ; in Gen- 

 trinus acuminatus, for example, the two basal joints together com- 

 pose less than one-half of the mass, with the first much shorter than 

 the second ; the basal joint is frequently subglabrous, at least toward 

 base, and especially in Baris with its immediate allies and in some of 

 the subgenera of Limnobaris ; in one of the subgenera of Centrinus 

 (Odontocorynus) it becomes conspicuously modified in the male. 



The mandibles vary greatly in structure, from stout, thick, arcuate 

 and broadly decussate to the long, straight, prominent and perfectly 

 non-decussate, without trace of internal denticulation, the latter 

 type being nearly similar in shape, but not in plane of motion, to 

 those of Balaninus, showing that Centrinus and Balaninus may have 

 a certain obscure relationship apart from their general similarity of 

 form. In Eunyssobia and Plocamus they move in a nearly vertical 

 plane, precisely as in Balaninus, but in spite of all these resem- 

 blances I am of the opinion that Balaninus is more closely allied to 

 the Anthonomini, and that it should constitute a simple tribe in 

 that vicinity. 



I have found the various modifications of the mandibles of posi- 

 tive value in delimiting the genera allied to Centrinus. It was the 

 opinion of Lacordaire that the forms assumed by the mandibles 

 were so erratic in this and allied tribes, as to be of very little use 



