CLASSIFICATION OF THE RHTNCHOPHOROUS COLEOPTEKA. 393 



Prosternnm not excavated ; Amycterid^. 



Prosternum excavated : ...... Byrsopid.e. 



Giilar margin not prominent, mentum large, concealing the 

 mandibles, which are not scarred at tip Brachycerid^. 

 b. Tarsi dilated, usually with a brush of hair beneath : 



Mandibles with deciduous tip, leaving a scar OTiORHYNcniDiE. 



Mandibles simple, usually pincer-tihaped. . CcjrculioniDjE. 



B. Antennoe with 11 separate joints. . . . Bkekthid^e. 



Concerning Amycteridpe and Brachyceridaj, but little need be 

 said. They are very peculiar and easily recognized forms, not 

 represented in our fauna. 



The first is Australian ; the antenna? are slender, and genicu- 

 lated ; the beak short and stout, deeply emarginate at tip, alike in 

 both sexes ; the buccal opening is very large, and the cavity is filled 

 almost completely by the jnandibles, which are convex, hairy on the 

 greater part of the front surface, defiexed, deepl}- concave beneath ; 

 the gular margin is thickened and prominent, so that a deep cavitj' 

 is seen between the gula and the mandibles, in which the mentum 

 and oral organs are concealed from view ; the e3'es are small and 

 nearly round in some, narrowed beneath in others. The front 

 coxfe are contiguous, the prosternum very short ; the elytra are 

 connate and extend far over the flanks, so that the side pieces both 

 of the meso- and metathorax are concealed. The dorsal segments 

 of the abdomen are membranous, except the last which is very 

 large, corneous, and convex,' more so in ^ than in 9 , in the former 

 it is truncate behind, exposing a" semicircular 8th segment, from 

 under whicli protrudes (Psalidura) a very powerful and complex 

 genital armature, consisting of a large pair of forceps, conical ob- 

 tuse, punctured and hairy, under which and seen only from below 

 is a pair of transverse, thin, polished, corneous plates, also meeting 

 on the median line ; between them and tlie forceps is a large deep 

 cavity. The ventral segments are scarcel}' less singular; the 1st 

 and 2d segments large, flat, connate, united b}' a sinuate suture; 

 3d and 4tli very short, separated by deeply excavated straight 

 sutures, 5th miich larger, in ^ very deeply and semicircularl}- ex- 

 cavated, almost to the base, with a tuft of stiff" bristles each side 

 at the front edge of the excavation ; in the $ this segment is flat, 

 and meets the last dorsal at tip in the usual manner ; on the sides 

 the lateral upward extension of the 5th ventral is very large, but 

 the spiracle is visible ; the extension of the 4th and 3d segments 

 2 



