144 GEO. n. HORN, M. D. 



The most striking sexual character is found in the different arma- 

 ture of the thorax of the uiale. This however occurs in the tirst two 

 species only. The clypeus of the male i.s usually truncate and that of 

 the female acute, or at least more so than the male. The only constant 

 and invariable character is found in the pygidium. This organ in the 

 male is always regularly convex, in the female broadly transversely 

 impressed aiid much smoother in tlje impressed space than the corre- 

 sponding portion in the other sex. The anterior spur of the u)iddle 

 and hind tibiae is sometimes stouter in the male than the female, 

 although the difference is neither very obvious nor important. 



S. .llltae^US Fab., Maimon Fab. 



General characters. — Form broadly oval, piceous or dark castaneous, 

 shining. Elytra with sutural stria visible only at apex. Outer angle 

 of the tip of the middle and hind tibite simply emarginate and with 

 unecjual spinules. 



Male. — Thorax with three horns, one from the middle of the an- 

 terior margin of the thorax, directed forward and upward, and one 

 from each side behind the middle directed inward and slightly back- 

 ward, of more robust form than the anterior horn. A moderately 

 deep fossa on each side between the bases of the anterior 

 md middle horns. Clypeus oval, subtruncate at tip, front 

 with two slight tubercles. Galea of mandibles tridentate, 

 inner and outer teeth very feeble, middle tooth long slender 

 md subacute. 



Female. — Thorax with an obtuse tooth at middle of an- 

 terior margin, behind which is a moderately deep fossa of 

 somewhat crescentic form, transversely wrinkled. Clypeus 

 similar in form to that of the male. Galea of mandibles 

 tridentate, inner two teeth similar and equal, outer broader and less 

 prominent. 



This species may be distinguished from all the others by the absence 

 of the sutural stria. I have, however, seen one specimen in the cabinet 

 of Mr Ulke with a very faint stria. The thoracic processes of the male 

 become at times very short. 



Occurs from New Jersey to Texas. 



S. .IllIiHIlUM Hurin. 



Gi'ueral characters. — Form oblong oval, piceous or castaneous, thorax 

 and head always darker than the elytra. Sutural stria entire 

 and moderately deep. Outer angle of the tip of the posterior 

 LJbiye distinctly tridentate and with one or two spinules unly 

 on each side of the middle tooth. 



