CLASSIFICATION OF THE EHTNCHOPHOROUS COLBOPTERA. 465 



B. Pygiclium horizontal; smaller: 



a. Antennae geniculate, clubbed : 



Terminal edge of last ventral acute, surrounding the last dorsal; 

 tibiae generally compressed and serrate. . . Scolytid^. 



b. Autennse straight : 



Ventral segments very unequal, antennae with annulated club. 



^ Apionid^. 



Ventral segments nearly equal ; antennas with 11 separate joints. 



Belid^. 



CALANDKID^. 



Elytra with the usual fold on the inner face near the side veiy 

 strongly developed ; diverging behind, and becoming gradually 

 effaced. 



Ventral segments 3d and 4th shorter, 1st and 2d connate; lat- 

 eral prolongations broad, imbricated ; the sharp edge for reception 

 in the elytral groove only developed on the 1st and 2d segments. 

 Dorsal segments coriaceous, pygidium large, triangular, rounded 

 at tip, declivous, alike in both sexes, though smaller in the third 

 sub-family ; last spiracle covered by prolongation of ventral seg- 

 ments. 



An excellent synopsis of the United States species of this 

 family has been published by Dr. G. H. Horn.* 



According to differences in the form of the mouth, the indig- 

 enous genera may be divided as follows : 



A. Pygidium exposed : 



Gular peduncle long, Calandrtd^. 



B. Pygidium covered by elytra : 



Gular peduncle broad, mentum concealed, . . . RhiniDjE. 



Gular peduncle moderate, mouth normal, .... Cossonid^. 



The mouth in this sub-family is formed upon a peculiar type not 

 seen in the genuine Curculionidse ; the gular peduncle is extremely 

 long and narrow, leaving the maxilloe visible in the buccal fissures ; 

 the mentum is small, sometimes concave, and the palpi not usually 

 visible. The mandibles are convex on their outer face and 

 strongly toothed at tip as in many Curculionidse. The beak is 

 long, curved and cylindrical, the antennse inserted at a distance 

 from the mouth, geniculate, with a large club which is corneous 

 and smooth at base, spongy and pubescent over the rest of the 

 surface. The eyes are transverse and finely granulated. The 



*Pi-oc. Am. Phil. Society, 1873. 



