236 GEO. H. HORN, M. D 



point of our fauna I can see no reason for admitting any other genus 

 than Silpha. 



Our species may be distinguished by the characters of the fol- 

 lowing table : 



A.. — Antennae inserted close to the eyes and distant from the margin of the 

 front. Middle coxse widely separated. 

 Eyes large, prominent, posterior femora much stouter in the males. 



surinamensis Fab. 

 Eyes not prominent, posterior femora similar in the sexes. 



Labrum broadly emarginate; third joint of antennae as long or longer 

 than the second. 

 Elytra squarely truncate, similar in the sexes, surface not costate. 



truncata Say. 

 Elytra sinuate or oblique at tip, more prolonged in the female, surface 

 distinctly costate. 

 Thorax emarginate at middle of base, surface pubescent, posterior 

 tibise of males straight. 



Intervals of elytral costse tuberculate lapponica Herbst. 



Intervals of costse flat trituberculata Kby. 



Thorax arcuate or truncate at middle of base, surface not pubescent, 

 posterior tibiae male arcuate. 



Thorax entirely black iniequalis Fab. 



Thorax bicolored noveboracensis Forst. 



Labrum deeply emarginate, third joint of antennpe shorter than second, 

 elytra with costae often feeble the intervals with anastomosing 

 lines. 

 Form broadly oval, thorax reddish-yellow with discal black space. 



americana Linn. 

 Form oblong-oval, color above entirely black often with bronze sur- 

 face lustre ramosa Say. 



B. — Antennae inserted close to the margin of the front and more distant from 

 the eyes. Middle coxse rather narrowly separated. Posterior 

 tibise of males unguiculate at tip. Labrum deeply emarginate. 



Form elongate-oval, (as in trituberculata) Ogtaca Linn. 



Form oval, (as in ramosa) bituberosa Lee. 



It may be here remarked that all our species occur in the region 

 east of the Rocky Mountains. The Pacific coast has not yet fur- 

 nished a species peculiar to it. 



S. snrinanicnsis Fab. — Form moderately elongate, depressed, piceous, 

 elytra with subapical, narrow orange-red fascia often broken in spots sometimes 

 wanting entirely. Head elongate-oval, sparsely finely punctulate, suddenly 

 constricted behind the eyes and with a deep transverse occipital impression. 

 Labrum broadly emarginate. Eyes large, oval, prominent. Antennae with 

 an elongated club of five loosely articulated joints, the last three pubescent. 

 Thorax transversely oval, emarginate in front, sides and base regularly arcuate, 

 margin broadly flattened posteriorly, surface sparsely finely punctulate, at the 

 sides and base more coarsely. Elytra as wide at base as the thorax, sides feebly 

 arcuate and gradually broader posteriorly, apex obliquely truncate, more pro- 



