SCOLYTIDAE. 513 



Mesosternura triangular, pointed behind, or slightly trun- 

 cate, episterna (Platypodiuce) excessively large, ascending 

 between the base of the prothorax and elj^tra with the epi- 

 niera small, posterior, and transverse, or with the suture 

 very indistinct; coxa) rounded, not widely separated. 



Metasternum long, sometimes (Platypodinas) very long; 

 side pieces parallel or nearly so, not dilated in front. 



Legs moderate in length, rather stout, front coxio almost 

 always contiguous ; middle and hind coxas more or less 

 separated ; tibi^ compressed, toothed, or Avitli transverse 

 ridges on the outer side rarely simple (Micraces) ; armed 

 with a terminal hook at the inner apical angle. Tarsi in 

 some genera filiform and 5-jointed; in others 4-jointed, with 

 the third joint either narrow or dilated and bilobed; last 

 joint long, with large, simple, divei'gent claws. 



The insects of this family are mostly of cylindrical form and 

 small size. They are the most formidable enemies of trees, some- 

 times devastating the forests, especially of conifers, by appearing 

 in incredible numbers: the burrows are chiefly between the wood 

 and the bark, though some genera penetrate more deeply (Xylo- 

 terus, etc.). The patterns made by them are complex and vary 

 according to genus and species ; those of several European 

 species are figured in the excellent work of Ratzeburg:,* and since 

 descriptions of our species are now accessible, so that their iden- 

 tification is easy, we trust that those interested in the ])reservatiou 

 of our forest trees may direct their attention to this important 

 subject. Specimens of the ravages of these insects should be 

 carefully collected, with individuals taken from the burrows, and 

 these should be deposited in some museum where llicy will be 

 carefully preserved for future study. 



The great differences exliil)ited by Platypus and its allies, indi- 

 cate the propriety of separating them as a distinct sub-family, a 

 course already adopted by Lacordaire. 



First joint of tar.si as long as tho others unitod. Pi.atypodin-i?. 



Fir.st joint of tarsi niucli shorter than the others united. Scolytin.k. 



Sub-Family I.— PLATYPODIXJ^. 



Head large, not covered by the ]n"othorax, front wide, oblique, 

 or vertical; labruni small, but distinct. Beak wanting; even 



* Die Forst-Insecten, vol. i. 



33 



