G6 COLEOPTERA OP NORTH AMERICA. 



Two groups, considered by Erichson as tribes, and reunited by 

 Kraatz (Insecten Deutschlands, II), may be formed : — 



Palpi with the last joint very small, subulate. P^ederi. 



Palpi with the last joint equal to the preceding. Pinophili. 



Group I. — Pasderi. 



The genera of this group are numerous, and are found under 

 bark, under stones, and near water. The form of the palpi rea- 

 dily distinguishes them from the second group. 



A. Hind tarsi with the fourth joint not lobed (presternum behind the coxae 



membranous) ; 

 Antennae geniculate. Cryptobium. 



Antennas straight ; 

 Hind tarsi with the joints 1 — 4 nearly equal ; 

 Thorax subquadrate ; labrum bilobed. Lathrobujm. 



Thorax narrowed in front ; labrum 4-toothed. Scop^ds. 



Hind tarsi with the joints 1 — 4 decreasing gradually in length ; 

 Thorax narrowed in front ; 



Labrum 4-toothed (last two segments of abdomen elongated). 



Echiaster. 

 Labrum with two acute teeth. Stilicus. 



Thorax subquadrate ; 



Labrum with two small teeth. Lithocharis. 



Labrum rounded, emarginate at tip. Dacnochilus. 



Labrum entire, elytra very short. Liparocephalus. 



B. Hind tarsi with the fourth joint lobed ; 



Last joint of maxillary palpi slender, very minute ; 



Elytra longer than the thorax. Sr/inus. 



Elytra shorter than the thorax. Stilicopsis. 



Last joint of maxillary palpi obtuse. P.ederus. 



Group II.— Pinophili. 



Yery elongated cylindrical species, sometimes of large size, and 

 found under bark of trees; some species of Palaminus are also 

 found on leaves of trees. Our genera are but two, both of wide 

 distribution : — 



Abdomen distinctly margined. Pixophilus. 



Abdomen not margined. Palamisus. 



Tribe V.— STEOTWI. 



In this tribe the prothoracic spiracles are concealed by the 

 inflexed portion of the pronotum; the anterior coxa? are small, 



