SCOLYTIDAE. 519 



declivity, which is sharply margined and acutely toothed. The 

 club of the antennae, as in the grouj) Xylebovi, is entirely corne- 

 ous on the inner face, but is not obliquely truncate on the outer 

 face. The sensitive surface is more or less distinctly defined, and 

 is divided by two sutures which are more or less curved or angu- 

 lated in our species, but are described in some ICuropean species 

 as straight, thus showing an afiBliation with Dryocoetes of the 

 preceding group. The tibias are coarsely serrate, and the tarsal 

 joints 1-3 are rather stouter than in the preceding groups. 



Our species represent but one genus, Tomicus, which may be 

 divided conveniently according to the form of the sutures of the 

 antennal club. Species occur in all parts of our country under 

 the bark of coniferous trees. 



Grouij V. — Micraces. 



The funicle of the antenme is G-jointed, the outer joints broader; 

 the club is pubescent and usually marked with sutures on both 

 sides, as in the group Corthyli, but these sutures are usually very 

 much curved, though sometimes nearly straight; the basal joint 

 is long, and in one sex is fringed on the front margin with very- 

 long hairs ; the eyes are transverse, coarsely granulated, either 

 distant or contiguous beneath. The prothorax is produced over 

 the head, rounded and asperate in front, and its anterior opening- 

 is very oblique as in most Pityophthori. The elytra ai'e usually- 

 punctured in rows, convexly declivous behind, then concave near 

 the tip, and sometimes asperate with small granules ; the suture 

 is produced into a sharp point, except in T. fimbricornis. The 

 tibiae are compressed, armed with a terminal hook, outer edge 

 acute, not at all toothed (or but slightly so in 31. rudis), and 

 fringed with long hair; the front paii" are as broad at base as at 

 tip ; the joints of the tarsi 1-3 are rather stout in all the species 

 except 31. hirtcUa, where they are longer and more slender ; the 

 fourth joint is small, and the fifth long, slender, with divergent 

 simple claws. Although important structural differences are seen 

 in the species, we regard them as constituting bu.t two genera. 

 This group is excellently defined by the 0-joiuted funicle, and the 

 broad parallel front tibiae. 



Club pubescent and annulated on both sides, outer joints ut funicle sIiErlitly 

 broader, not fringed; elytra, aculeate at ti|>. Micracia. 



