SCOLYTIDAE. 515 



the chief peculiarities will be pointed out under the appropriate 

 heads. 



The genera which occur in our fauna indicate the following 

 tribes : — 



1. Prothorax not prolonged over the liead, wliicli is oblong and j)rominent ; 



tarsi witJi fourth joint smaller or indistinct; third joint usually bi- 



lobed. 2. 



Prothorax prolonged over the head, wliich is deeply immersed and 



globose ; tarsi filiform, 5-jointed. Tomicini. 



2. Ventral surface ascending obliquely. Scolytini. 

 Ventral surface regularly cylindrical. Hylukgini. 



Tribe I.— TOMICINI. 



Although the genera of this tribe are the farthest removed from 

 Cossoninag by their characters; they are iu some respects the 

 most nearly allied to Platypus, with which the family must natu- 

 rall}^ commence, on account of the relations between the latter 

 and BrenthidaB. 



The head is globose, or nearly so, and deeply immersed iu the 

 prothorax; the eyes arc transverse, sometimes divided (Xylo- 

 terus) ; the front is not prolonged into a beak ; the antennae are 

 inserted near the base of the mandibles; the scape is long and 

 stout, the funicle short, compostjd of from one to five joints, the 

 mass large, compressed, varying in form and strnctuve according 

 to genus. Prothorax more or less cylindrical behind, prolonged 

 in front over the head and much rounded, so that the anterior 

 opening becomes very oblique, or even sometimes almost hori- 

 zontal; the sculpture is peculiar, and consists for a greater or less 

 distance from the apex of sharp granules or little spines; behind 

 the surface is smooth or punctured; the side margin is not dis- 

 tinct. Tiie mesonotum is never carinate as in Platypus. Elytra 

 suddenly declivous in front, so that the edge fits against the base 

 of the pronotum; usually obliquely excavated and toothed on the 

 posterior declivity; ridge on ituier surface near the outer margin, 

 effaced near the tip; groove very deep and narrow. Pygidium 

 entirely covered. Mesosternum acute behind, side pieces ob- 

 liquely divided, epimera small, not attaining the coxa;. Metaster- 

 nuni rather long, side pieces narrow. Ventral segments five ; first 

 and second longer, closely united ; fifth longer than the fourth, 

 rounded behind, edge acute, fitting under the elytral edge. Front 



