138 GEO. H. HORN, M. D. 



In the first section, evidences of a tendency to a protuberance of 

 the thorax in front, are distinctly visible in the female. When a .^lij^ht 

 protuberance does not exist in the female there are on the anterior 

 inarp;iti of the thorax two slight depressions visible, one on each side 

 midway between the median line and the anterior angle. The pro- 

 thoracic protuberance of the male varies greatly in development, in 

 its greatest size the process fjrms a plate of variable width, usually 

 much longer than wide projecting three-fourths as far as the tip of 

 the clypeus, more or less deeply eniarginate at tip and with tiie angles 

 thus formed divergent. In Hecate a slight process projects downwards 

 from the bottom of the emargination and is itself deeply notched form- 

 ing two small teeth, while in Janus a slight tooth is seen near the tip 

 of the diverging angles. From the size above described, the pro- 

 thoracic process may be reduced to a mere transverse tubercle. The 

 males of all the species have much longer, more slender and more 

 arcuate anterior tibiae than the females and the terminal spur is shorter, 

 more robust and more arcuate. 



In the second section the form of the anterior tibiae furnishes the 

 only guide for distinguishing the sexes. 



In nearly all the species the head is transversely bicarinate in the 

 two sexes,, and where the thoracic protuberance is strongly marked in 

 the male these carinas di^appear and in very nearly all the females ot 

 all the species the carinae are more strongly marked than in the males. 

 These two carinas are situated, the anterior on the clypeo-frontal suture, 

 the posterior on the vertex between the eyes. 



The first section contains three species. 



Body blaek, opaque, thorax finely granulate, elytra finely chagrined and 

 with two rows ol" fine granules on each interspace. Vertical carina of male 

 simple Ileeate. 



Body bronzed or greenish, shining, thorax punctured, elytra usually sliiniug not 

 granulate. Vertical carina of male elevated at each extremity into a horn 

 of variable size or an acute tubercle JailUS. 



Body black, sub-opaque, thorax sparsely punctured ; elytra very finely chagrined 

 and irregularly biseriately punctured. Vertical carina of male elevated at 

 each extremity into a long slender horn vellitiiius. 



O. Ileoafe Vanz., hastalor Fah., latebrasus Fa,h., obtectus Beau v. , (So.yi Cast. — 

 Black, op:i(jiie, .-'jjarsely clothed with short greyish hair. Thorax moderately 

 densely granulate, median line at base very finely impres.sed. Elytra finely 

 striate, intervals finely chagrined and with two or three rows of fine granules. 

 Pygidium coarsely punctured, at base opaque and granulate. Body beneath 

 shining, coarsely but sparsely punctured. Length ..S4 inch; 9 mm. 



Male. — Margin of head moderately refle.xed, in front elevated in a slender 

 triangular jjrocess, on each side slightly sinuate. Clypeus smooth at middle, 

 punctured and wrinkled at the sides, front and verte.x very sparsely punctate. 

 Clypeal carina feeble or absent, vertical carina arcuate and feeble, frequently 



