Casey — A Revision of the American Paederini. 73 



14 — Gular sutures nearly straight, feebly converging posteriorly through- 

 out and most approximate at or near the base of the head ; maxillary 

 palpi unusually elongate and slender, the fourth joint very slender and 

 aciculate. Europe and America Tetartopeus 



Gular sutures arcuate, mo?t approximate at or before the middle of the head, 

 gradually diverging thence to the base; maxillary palpi rather less 

 elongate and stouter; head nearly similar; species small in size. 

 America Deratopens 



15 — Parallel, the neck wide, rather more than half as wide as the head, 

 the latter transversely truncate at base, the labrum deeply and broadly 

 cleft to the base, the lobes long, moderately diverging, parallel, slightly 

 everted and evenly rounded at tip; fourth palpal joint evenly conical, 

 not compressed; gular sutures widely separated, parallel, becoming 

 feebly convergent toward base, where they are most approximate ; 

 antennae half as long as the body; prothorax short and broad, with 

 the apical angles distinct, the prosterum short before the coxae as in 

 Lathrobium; elytra a little wider and longer than the prothorax, with 

 the punctures subserial in arrangement; legs rather short and stout, 

 the hind tarsi moderately long and slender, with the first, third and 

 fourth joints subequal, the second a little longer, the fifth as long as 

 the preceding four combined; claws unusually long and strong. 

 Europe *Achenium 



Parallel and rather broad, nearly as in Achenium, the head, prothorax and 

 elytra proportioned almost similarly; labrum very short, the emargiua- 

 tion extending throughout the width, the sides not lobiform; gular 

 sutures parallel and broadly arcuate, not very widely separated and 

 most approximate at the middle; fourth palpal joint compressed; neck 

 fully three -fifths as wide as the head; elytral punctures confused, not 

 at all serial in arrangement; legs rather long, moderately stout, the 

 hind tarsi long, slender, with the basal joint much elongated, subequal 

 in length to the next two combined and longer than the fifth. 

 Europe *Scimbalium 



16 — Gular sutures less separated, converging posteriorly, becoming most 



approximate at or near the base of the head; basal joint of the hind 

 tarsi distinctly shorter than at the second 17 



Gular sutures parallel, broadly arcuate to nearly straight, most approxim- 

 ate at or near the middle of the post-oral surface or at least distinctly 

 before the base 18 



Gular sutures generally more widely separated, most approximate ante- 

 riorly, gradually more or less divergent posteriorly, becoming most 

 distant at the base 19 



17 — Body large, stout, parallel, the head arcuato-truncate at base, with very 



broadly rounded obsolete angles, the neck but little more than a 

 third as wide; lobes of the labrum obliquely subquadrate; prothorax 

 oblong-suboval, the anterior angles rounded; abdominal segments 

 feebly impressed at base; legs and tarsi thick. Eastern America. 



Enlathrobinm 



Body rather large, more slender and convex, parallel, the head circularly 



rounded or feebly subtruncate behind, the neck about two-fifths as 



wide; lobes of the labrum evenly rounded throughout their contour; 



