AMERICAN COLEOPTERA. 155 



The under side of the thorax presents but little variation. Erichson 

 and many following him have used the process behind the anterior 

 coxae as a point of departure in the primary division of the species. 

 An examination of a large number of specimens convinces me that 

 this character has no value whatever. This piece which is the 

 epimeron varies in size in the species and may be long or short, 

 opaque, translucent, or transparent, but there is no such division as 

 corneous and membranous. It is in fact in every species in our 

 fauna semi-corneous. I have been obliged to reject it in arrangement 

 of the species. 



The scutellum varies in being smooth or punctured. 



The elijtra vary in punctuation in the species, but variation within 

 specific limits must be admitted. 



The abdomen varies in sculpture with the elytra and is usually 

 more sparsely punctured. 



The anterior tibiae are rather inconspicuously spinulose externally, 

 the middle and posterior very plainly so except in Isevigatus. 



The tarsi are hairy on their upper side in all the species, except 

 vernix andyero.-c in which they are smooth and without hairs. 



The lahrum presents two distinct forms, and by this means the 

 genus can be divided into two portions much more satisfactorily than 

 by any other method. The normal form of labrum is that in which 

 there is an acute incisure at middle so that a bilobed form is presented. 

 In many however, the labrum is entire and either broadly arcuate in 

 front (inohchinus)^ or truncate. 



The affinities of Quedius have already been hinted at and are 

 plainly with Bolitohius through vernix, and with Philontlius through 

 the species with the entire labrum. 



The sexual characters are remarkably uniform and consist in the 

 male, of an emargination of the sixth ventral (truncate in vernix^, 

 a greater dilatation of the anterior tarsi, and frequently a broader 

 head. 



Based on the foregoing remarks, the following method of arrange- 

 ment is presented : 



A. — Tarsi above hairy. Thorax with three diseal punctures. 



Labrum bilobed 1. 



Labrum entire, either arcuate or truncate 10. 



1. — Antennae fusiform explanatus. 



Antennae filiform or slightly thicker externally 2. 



2. — Hind tibiae distinctly spinulose externally 3. 



Hind tibiae not spinulose 9. 



