BY THOMAS G. SLOANK. 445 



AA. Metepisterna but little longer than broad, bordered, but not sulcate, 

 along inner side, outer margin not strongly raised... 0. parviceps SI. 

 ii. Prosternum with intercoxal part not bordered. Humeral angles of elytra 

 edentate. 



B. Black species. 



C. Opaque. Elytra finely and lightly striate; interstices flat, bearing 

 some minute punctures. (Prothorax with a fine seta on each side 



of base a little within basal angle). Size large, r2'5-14mm 



0. oblongus Cast. 



CC. Nitid. Elytra finely, but decidedly, striate; interstices without 

 minute punctures. (Male with intermediate tibiffi arcuate). Size 

 small, 9-10'5 mm. 



D. Elytra finely and simply striate; scutellar striole faintly indicated 

 by a row of punctures; interstices quite flat. Size 10-5 mm. .. 

 O. irisulcahis Cast. 



DD. Elytra more strongly striate; scutellar striole strongly impressed; 

 interstices subconvex. Size 9-10 mm 0. fitzroyensis Macl. 



BB. Bronzed species. 



E. Labrum with six separate setigerous punctures along anterior margin. 



F. Elytral striae strongly erenulate; ninth interstice forming a narrow 



border to eighth. Intermediate tibiee in male arcuate. Size 



large, 14'5mm 0. denisonensis C&st. 



FF. Elytral strife finely erenulate, or subcrenulate, under a lens; 

 ninth interstice not forming a border to eighth. Intermediate 

 tibise in male not bent. 

 G. Size large, 12'5-13-5mm. 



H. Elytra with marginal channel constricted near base ; inter- 

 stices subconvex; .scutellar striole strongly impressed 



,0. waterhousei Cast. 



HH. Elytra with marginal channel not constricted near base; 



interstices quite flat; scutellar striole feebly marked 



0. frogrjatti Macl. 



GG. Size small, 9-11 mm. 



J. Elytral striaa and interstices as in 0. waterhousei; scutellar 

 striole well marked. Prothorax with evident lateral basal 



impressions 0. impressus Chaud. 



JJ. Elytra finely striate; interstices depressed; scutellar striole 

 faint. Prothorax not perceptibly impressed on each 



side of base 0. inodestus CdiSi. 



EE. Labrum with three punctures (middle puncture bearing four fine 

 sette) along anterior margin 0. hostocki C&s,i. 



