374 SCOLYTID^E. 



[LeConte. 



and in Hylastes assume very much the same form as in Cossonidce, to 

 which some of these insects bear a strong resemblance. They may be dis- 

 tinguished, however, by the compressed and serrate or spinulose tibiae. 



The third joint of the tarsi is frequently dilated and bilobed, and the 

 fourth joint, less conspicuous than in the preceding tribes, is sometimes 

 quite indistinct. The first and second ventral segments are always 

 separated by a well-defined straight suture, more deeply impressed than in 

 Tomicini. 



The prothorax is Insinuate behind, with a well defined antescutellar 

 angle in some of the species of all the groups except Hylastes. They thus 

 manifest a tendency to the Anthribidce (Choragus, &c.), as Hylastes does 

 towards the Cossonidce. 



In several genera the front coxae are separated by the prosternum, and 

 in Dendroctonus and the allied European genera Hylurgus and Blastopha- 

 gus the second and third ventral sutures are curved backwards at the sides. 

 In Hylastes the prosternum is deeply excavated for the reception of the 

 short beak. In all these characters resemblances are seen to different 

 tribes of Curculiomdce. 



Our genera indicate the following groups : 

 Club oval, annulated, scarcely compressed 2. 



" strongly compressed, not annulated, pubescent on both 



sides Polygraph!. 



2. Joints of club separated Phloeotribi. 



" " closely connate, as usual 3. 



3. First and fifth ventral segments elongated, scutellum not 



depressed * 



Ventral segments nearly equal and scutellum depressed H y inrgi. 



4. Prosternnm very short, funicle with few joints Cryptiirgi. 



Prosternum excavated ; funicle 7-jointed Hy lastes. 



Group I. Polygraph!. 



This group is sufficiently defined by the club of the antennae being large, 

 strongly compressed, pubescent and sensitive, and without sutures on both 

 sides, and by the antennae being inserted as usual at the sides of the front. 

 The tibiae are broadly dilated, obliquely rounded at the apex, and finely 

 serrate ; th? third joint of the tarsi is not bilobed, and the fourth, though 

 small, is distinct. The basal margin of the elytra is acute and serrate. 

 Two genera occur in our fauna : 

 Eyes slightly emarginate, funicle attached at the 



side of the club, outer joints slender CHRAMESUS. 



Eyes completely divided, funicle attached at the 



end of the club, outer joints gradually stouter POLYGRAPHUS. 



OHRAMESUS Lee. 

 Rhopalopleurus Chap. 



Body stout, oval, convex, clothed with small scales and stout, erect 

 bristles, which are not striate as in Hypothenemus Mspidulus (p. 355). 



