LeConte.] 



TOMICIKT. 367 



united by a ridge, tlie angles of whicli are very little prominent; the apical 

 ridge is long, and between it and the last mentioned tooth is an acute tooth 

 which is equally prominent. The prothorax is nearly as long as the elytra, 

 more finely and densely asperate in front, and more finely punctured behind. 

 The sutures of the antennal club are nearly straight. 



12. T. latidens Lee, Tr. Am. Ent. Soc. 1874, 72, 



California, at Lake Tahoe; Mr. Crotch. This species is smaller (3 mm.; 

 .14 inch), than T. pini, and of moi'e slender form. It is easily distinguished 

 from all the other species by the much more deeply concave declivity of 

 the elyti'a; the cusp of the second interspace is acute; the teeth of the fourth 

 and fifth are united together, forming a ridge which has three distinct 

 cusps, of which the middle one is more prominent; the tooth be- 

 tween this ridge and the terminal margin is unusually prominent. The 

 stria are composed of deep close-set punctures, and the interspaces are 

 marked with rows of small punctures. The sutiires of the antennal 

 club are nearly straight. 



13. T. concinnus Lee, Tr. Am. Ent. Soc. 1868, 164; Bostrichux cone 

 Mann., Mosc. 1852, 358. 



Alaska, three specimens. Length 4.2 mm.; .17 inch. A very distinct 

 species, with the elytra confusedly punctured ; the declivity oblique, nearly 

 flat, punctured, with the sutural stria scarcely distinct; the teeth are but 

 three each side, of which the anterior one is small, and the third longer 

 and larger than the second. 



Group Y. Micracldes. 



The funicle of the antennse is 6-jointed, the outer joints broader; the club 

 is pubescent and usually marked with sutures on both sides, as in the group 

 Cortliyli, but these sutures are usually very much curved, though some- 

 times 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 protho- 

 rax is produced over the head, rounded and asperate in front, and its 

 anterior opening is very oblique as in most Pityophthori. The elytra 

 are usually punctured in rows, convexly declivous behind, then con 

 cave near the tip, and sometimes asperate with small granules ; the 

 suture is produced into a sharp point, except in T. fimhricornis. The tibiae 

 are compressed, armed with a terminal hook, outer edge acute, not at all 

 toothed (or but slightly so in M. rudis), and fringed with long hair; the 

 front pair are as broad at base as at tip ; the joints of the tarsi 1-3 are 

 rather stout in all the species except M. hirtella, Avhere 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, I regard them as constituting but two genera. This 

 group is excellently defined bytlie 6-jointed funicle, and the broad parallel 

 front tibiae. 



