68 



76 (75; 



77 (78; 



78 (77 



79 (84; 



80 (83 



81 (82 



82 (81 



83 (80; 



84 (79) 



Clypeus generally more or less impressed at the apex but the 

 true emargination not deep. 



Mandibles for the most part red; propodeum with dull surface 

 and hardly visible sculpture. O. aprepes, sp. nov. 



Mandibles generally for the most part black; propodeum with 

 some coarse shallow punctures or rugose. 



Head above the antennae densely, mesothorax strongly and 

 closely, punctured. 



Second ventral segment of abdomen with no depression behind 

 the costae or with only faint traces of one. O. lanaiensis, P. 



Second ventral segment with a shallow but distinct depression 

 (second dorsal segment quite strongly subtuberculately 

 raised from the base). O. konanus., P 



Head above the antennae more or less remotely or sparsely 

 punctured, mesothorax not strongly punctured. 



Clypeus wide, seen from in front not much produced; face with 

 a median yellow spot. Pseudopterocheilus congruus, Sm. 



Clypeus long and narrow much produced; no yellow frontal 

 spot. Chelodynerus chelifer, P. 



Females; antennae twelve-jointed, simple at the apex. 



Mandibles extremely long and narrow with the teeth more or 

 less obsolete; a distinct and rather long cheek between the 

 eye and mandibles. C. chelifer, P. 



Mandibles normal ; no distinct cheeks. 



Maxillary palpi extremely long and regularly fringed with long 

 hairs. P. congruus, Sm. 



Maxillary palpi normal. 



Mesothorax with fine sparse punctures, sometimes almost 

 effaced, the surface very dull with extremely dense minute 

 interstitial punctures very distinct. O. sociahilis, P. 



Mesothorax always distinctly, sometimes strongly or densely 

 punctured, the surface between the punctures in some 

 species more or less shining, the minute interstitial punc- 

 tures in some indistinct or nearly effaced. 



Mandibles nearly entirely red. O. molokaiensis , P. 



Mandibles wholly or for the most part black. 



Mesothorax closely and often strongly punctured. 



Apex of clypeus truncate or very slightly emarginate, basal 

 abdominal segments not pale along the apical margins. 



Depression of second ventral segment of abdomen shallow but 

 quite distinct. O. konanus, P. 



Depression of second ventral segment scarcely or not at all 

 perceptible. O. lanaiensis, P. 



Apex of clypeus very distinctly emarginate, the true emargina- 

 tion not very feeble; abdomen generally with the apical 

 margin of the basal or two basal abdominal segments pale. 



O. smithii, D. T. 



Mesothorax somewhat remotely and not strongly punctured. 



O. insulicola, Bl. 



