152 Trans. Acad. Sci. of St. Louis. 



wide, the anterior not in the least dilated or thickened ; species very 

 minute, not distinctly punctured; male sexual characters nearly as in 

 Sciocharis, except that the apex of the fifth segment is lobed in the 

 middle. Southern Atlantic States Sciocharella 



6 — Labral teeth small and inconspicuous; prosternum never carinate 



throughout its length except in a few abnormal members of Medon.. 7 



Labral teeth long, acute and very conspicuous; prosternum carinate 



throughout its length; gular sutures converging and most narrowly 



separated basally 12 



7 — Basal joint of the posterior tarsi equal in length to the second, the 



first four short and subequal, the anterior very slightly dilated; palpi 

 normal ; gular sutures rather narrowly separated, evenly, fe< bly arcuate, 

 very rapidly diverging at base, most narrowly separated at a little be- 

 fore the middle; antennae rather thick, gradually enlarged distally, 

 the third joint distinctly longer than the second; eyes moderate; neck 

 about half as wide as the head; prosternum not at all carinate at any 

 point; integuments very coarsely, densely sculptured and dull, the 

 species small in size. Nearctic regions, cast of the Rocky Mountains. 



Trachysectus 



Basal joint of the hind tarsi distinctly longer than the second, the tarsi 



more elongate 8 



8 — Labrum with a rather broad sinus at the middle including the two teeth, 



which are very small and uot as anteriorly prominent as the sides of 

 the labrum; species small, with the elytra very small, shorter and nar- 

 rower than the prothorax; eyes rather small; neck two fifths as wide 

 as the head; gular sutures well separated and subparallel but obsolete 

 or very feeble; antennae short, moderately thick, filiform, not en- 

 larged distally, the basal joint thicker than the remainder; prosternum 

 rather strongly carinate except anteriorly; posterior tarsi very slender 

 and filiform, the anterior slightly dilated; integuments rather coarsely, 



densely sculptured and dull. Appalachian region Hemimedou 



Labrum with a narrower median notch, the two teeth more advanced than 

 the lateral parts of the edge aud not included within the sinus 9 



9 — Anterior tarsi not dilated but only more or less strongly thickened; sex- 



ual characters very feeble 10 



Anterior tarsi strongly dilated, especially in the male; sexual characters 

 strongly marked 11 



10 — Gular sutures distant, broadly arcuate, becoming very widely diverg- 



ent toward base and most narrowly separated well before the middle; 

 species small, slender in form, polished aud sparsely punctate, the 

 elytra subequal to the prothorax in size; antennae moderately thick, 

 somewhat enlarged distally; labrum very broadly, angularly emarginate, 

 with a small feeble median sinus, the teeth very minute; eyes rather 

 well developed; neck a little less than half as wide as the head; ante- 

 rior tarsi spongiose beneath in both sexes; hind tarsi slender and fili- 

 form. Europe , *Hypoinedon 



Gular sutures of the same form as in Hypomedon but subobsolete; species 

 minute, slender, polished and sparsely, rather coarsely punctate, the 

 elytra shorter than the prothorax; antennae normal in structure; lab- 

 rum small, truncate, with a distinct rouuded median sinus and two well 



