NORTH AMERICAN COLEOPTERA. 71 



Anterior coxal cavities closed behind; tarsi not lobed beneath, with the fourth 



Joint small I. SILVANINAE. 



Anterior coxal cavities open behind; maxillae covered by corneous plates. 



ir. PASSANDRINAE. 



Maxillae exposed IH. CUCUJINAE. 



Anterior coxal cavities closed behind; tarsi with the third joint lobed. 



Fourth tarsal joint not smaller than the third IV. IIEMIPEPLINAE. 



Fourth tarsal joint very small V. TELEPHAXIXAE. 



Sub-family I.— SILVANINAE. 



Tarsi pentamerous in both sexes. Fourtli joint very small. ^Maxillae 

 exposed. Ligula entire, or sliglitly emarginated, rarely bilobed. An- 

 tennae terminated by a small, but distinct, club. 



Two genera are indicated as follows: 



Club of antennae formed by abrupt enlargement of last three joints. 



Silvanus. 



Club of antennae formed by gradual enlargement of joints Sfansibius. 



SII^VAXUS Lutr. 



Body more or less elongated, somewhat depressed. Labrum short. Mandibles 

 short, and provided with a densely ciliated membrane. Last joint of palpi grad- 

 ually .attenuated, or obconical, and truncated slightly at the extremity. Head 

 sub-quadrate. Eyes small, rounded and coarsely granulated. Antennae, with 

 joints one and two, larger; three to seven smaller, sub-equal; eight, smallest: 

 nine to eleven, forming a loose club. Elytra elongated ; sides parallel, or slightly 

 convex, not margined. Tarsi with first joint large: fourth very small. Elvtra 

 covering entire abdomen, punctato-striate. 



The species of this genus are small, found under bark, or in articles of 

 commerce, and many of them are cosmopolitan. All are punctured ; the 

 punctures on the elytra are circular impressions of rather larger size, and 

 are arranged in rows, so as to present, under low magnifying power, the 

 appearance of striae. There are in addition to these rows of punctures, 

 regular lines of setae, which, in general, are short, recumbent and bristle- 

 like, but which in some cases become so long and slender as to constitute 

 pubescence as in S. rectvs. 



The following arrangement may be adopted at present, there being two 

 very distinct divisions : 



A. — Lateral edges of prothorax strongly and acutely dentate. 



Genae large and distinct 1. Siiriiiaiiieiisis. 



B. — Lateral edges of protborax not dentate, finely granulate : genae voiy small, 

 or invisible. 

 Prothorax as long, or longer than broad ; sides more or less sinuate. 

 I'rothorax strf>n<;lv Uiirrowed behind. 



