Anterior tarsi narrowly dilated in the male, the dilated joints always longer 

 than wide. 



Gena? not dilated, maxilhe exposed, legs slender SCAPH1XOTUS, 



Genae dilated, maxillae covered. 



inner lobe of maxilla? with a row of long stiff bristles, legs very elon- 

 gate, the posterior unequal in the sexes. Elytra very feebly 



sculptured PEMPHUS. 



Inner lobe of maxillae with, at most, a few hairs and some silken 

 pubescence, legs moderate, similar in the sexes. Elytra striate 



or punctate '.BRENNUS. 



Anterior tarsi of male not at all dilated. 



G-enae dilated, covering the maxilla?, legs moderately stout C¥CHRUS> 



SPH.ERODERXS, Dej. 



Basal impressions of thorax broad and deep, and with coarse deep punctures 

 more or less confluent. 



Elytra oboval, sculpture decidedly granular 1.' nitidicollis. 



Basal impressions of thorax linear and not very deep, the punctures rather • 

 fine and not confluent. 



Hind angles of prothorax very obtuse 2. SteilOStOUlUS. 



Hind angles of prothorax well defined 3. canadensis. 



SCAPHIrVOTUS, Lair. 



Anterior tarsi of male moderately dilated, the first three joints papillose 

 beneath. 

 Thorax very widely margined, the hind angles prolonged backwards. 

 First joint of the anterior tarsi of the male papillose over three- 

 fourths of its surface 4. elevalus. 



Thorax with moderately widely reflexed margin. First joint of the an- 

 terior tarsus of the male with a slight papillose space at tip, 5. vid mis. 

 Thorax with very narrow margin. 



Anterior tarsus of male as in viduus 6. Guyolii. 



Anterior tarsus of male as in elevatus 7. Ridillgsii. 



Anterior tarsi of male more distinctly dilated and densely spongy pubescent 

 beneath, the first joint so clothed over nearly its entire surface. 

 Thorax very narrowly margined 8. Andrewsii. 



PEMPHUS, Motsch, 



The inner lobe of maxilla? is furnished in this subgenus with a row of long 

 stiff bristles, while all the other species of Cychrus have there merely 

 silken hairs with a few shorter and stiffer hairs placed in a correspond- 

 ing row. The femora of the male are longer than those of the female. 

 "We have but one species 9. angusticollis. 



BRIvVAIS. Motsch. 



Head cristate to a greater or less extent, gula deeply transversely impressed. 

 Basal joints of antennae very stout and longer than the third, gena? 

 deeply incised. 

 Anterior tarsi of male with three joints pubescent beneath, fourth with a 

 brush of hair. 

 Front strongly cristate, occiput deeply transversely impressed, basal 

 impression of thorax deep. Elytra with rows of moderate 

 punctures which are often more or less confused . . 10. cristatllS. 

 Front feebly obtusely carinate, occiput not impressed, basal impress- 

 ion of thorax feeble. Elytra striate, stria? distantly punctured, 



II. rugiceps. 



