368 Trans. Acad. Sci. of St. Louis. 



Maxillary palpi shorter and stouter, compressed, the very short, obtusely 

 conical fourth joint evidently shorter than the third; antennae nearly as 

 in XantholinuB, the epistoma shorter but much broader, truncate; median 

 frontal grooves strong, parallel, the ocular subobsolete; gular sutures 

 arcuately converging, fine, becoming very approximate behind the 

 middle; head rounded at base; punctures extremely fine and sparse 

 throughout, the integuments highly polished; hind tarsi with the two 

 basal joints equal. North America (Souoran regions) Xestolinns 



U— Body moderately large, the head well developed, nearly as in XanfAo- 

 linus and larger than in Gyrohypnus, the gular sutures united from well 

 before the middle to the base; epistoma small, truncate; maxillary palpi 

 with the third joint shorter than in Xantholinus, the fourth much 

 longer, stouter than in Gyrohypnus and acuminate only in apical half; 

 median frontal grooves well developed, parallel, the ocular grooves 

 obsolete and represented by feeble depressions near the eyes; punc- 

 tures normal, rather coarse; hind tarsi with the first two joints equal. 

 Subtropical Altantlc North America Lissohypnui 



15 — Body moderately stout and rather smaller, the elytra less developed 



than usual, the head broadly rounded basally, the eyes rather small; 

 antennae unusually stout, the third joint as long as the next two com- 

 bined, constricted toward base and strongly dilated apically, peduncu- 

 late and much longer than the second; maxillary palpi with the third and 

 fourth joints elongate, the latter unusually slender for the present group 

 and gradually narrowed to the obtuse apex almost throughout, some- 

 what shorter than the third; gular sutures fine, arcuately converging, 

 becoming very approximate toward base; median frontal and oblique 

 ocular grooves fine, subequal in length and visibility; punctures fine 

 and sparse, the integuments polished; hind tarsi more slender and 

 elongate than usual, the first joint scarcely as long as the second. 

 Euro'pe *IdioIinus 



16 — Pronotal punctures as in the preceding genera, very sparse and disposed 



in a few more or less irregular series 17 



Pronotal punctures confused in arrangement and usually much more nura- 



10 



erous *" 



17 Frontal grooves very long, deep and conspicuous, the oblique ocular 



grooves as long and conspicuous as the median; fourth palpal joint 

 subcylindric, very slender, usually quite distinctly shorter than the third 

 and only moderately oblique in insertion; mandibles grooved externally 

 as usual; gular sutures uniting just behind the middle and thence 

 •coarse and single to the base; under surface of the head longitudinally 

 impressed near the sides, the impression bounded externally by an ob- 

 tusely rounded ridge; second antennal joint longer and thicker than the 

 third, the outer joints only moderately thick as in Xantholinus; tarsi 

 obviously thickened toward base; punctures of the head and pronotum 

 very few in number but remarkably coarse. Palaearctic and Nearctic 

 regions Leptacinns 



Frontal grooves shorter and finer, the oblique ocular shorter and much 

 fainter than the median; antennae similar; fourth palpal joint equally 

 slender but more conical, slightly shorter to somewhat longer than the 

 third and strongly oblique in insertion; gular sutures finer, arcuate, 



