508 COLEOPTERA OF NORTH AMERICA. 



are convex on the inner face, and the apical teeth are everted, 

 tliough this is probably a group or generic character as in certain 

 tribes of Calandrinaj. The club of tlie antennae varies in form 

 according to genus, and is not annulated. The tarsi also varj^, 

 the third joint being narrow in some genera, wide and bilobed in 

 others. 



But one representative, Yuccaborus frontalis, occurs in Cali- 

 fornia, which indicates a genus allied to Rhina and Harpacterus. 



Sub-Family III.— COSSONIN^. 



The abnormal form of mouth seen in the two preceding sub- 

 families is here replaced by the ordinary buccal cavity and mouth 

 organs seen in Curculionidse. The gular peduncle is rather 

 l)road, not very long, the mentum and ligula with its palpi are 

 distinct and moderately large, and the maxillaj and palpi are well 

 developed. The beak varies greatly, being sometimes rather long, 

 and moderately slender, sometimes so short and stout as to become 

 indistinct. The antennas are inserted at a variable distance, being 

 sometimes basal, sometimes nearly apical; the scape generally 

 extends beyond the eyes; the funicle has from four to seven joints; 

 the club is small, oval, partly corneous in some genera, and but 

 feebly annulated. The front coxa? are sometimes widely separated, 

 sometimes almost contiguous. The thighs are unarmed, and the 

 tibiae are armed in our genera with a long curved spine at the 

 inner apical angle ; the tarsi are variable, the third joint is usually 

 not broader; in one genus, Dryophthorus, by an exception other- 

 wise unknown in the family, and repeated again only in I'latypus 

 and some other genera among the Scolytida^, the tarsi are dis- 

 tinctly 5-jointed. 



Neglecting the number of joints in the funicle of the antennas 

 as being rather of generic than tribal value, the few genera repre- 

 sented in our fauna may be divided as follows: — 

 Beak long, not dilated <tt tip; body uneven, covered with a, crnst. 



DKYOrUTHOEIXI. 



Beak long or moderate, usually dilated at the end, with rapidly descend- 

 ing antennal grooves, front coxje distant, body sometimes depressed. 



CoSSONlNI. 



Bt'ak usually short, always continuous with the front, and equally stout ; 

 front cox?e approximate; body cylindrical. PiIiy.vcolini. 



