Notes on Hawaiian Wasps. 133 



largely red then the wings have very conspicuous blue 

 iridescence. 



18. (19) ($ . Clypeus very deeplj' emarginate ; sides of first and second 



segments obscurely red ; mesothorax very dull, with very 

 feeble or obsolete punctures ; a median yellow spot behind 

 the antennpe. 0. axestes, P. 



19. (18) (t . Clypeus not very deeply emarginate ; if deeply then the 



mesothorax is strongly and densely punctate. 



20. (21) Depression of second ventral segment deep, very wide, im- 



pressed to the level of the costse very widely at the base ; 

 front of head dull with fine, often nearly obsolete, 

 punctures ; second dorsal segment simple, when seen in 

 profile not raised into a distinct hump at its basal third. 

 0. obsat;re-p}i7ictatii,s, Blackb. 



21. (20) Depression of second ventral segment not extremely wide, 



nor widely sunk at the base to the level of the apices of 

 the costte ; front of head densely punctured or somewhat 

 shining, or the second dorsal segment of abdomen is 

 rather strongly raised to a point at its basal third. 



22. (2.3) ^ . Apex of clypeus very distinctly dentately-emarginate ; 



mandibles red ; propodeum rugose. 



0. dyseriithrins, P. var. 



23. (22) ^ . Apex of clypeus sometimes depressed and dentate, but 



only slightly emarginate or truncate ; mandibles red 

 or dark ; propodeum not rugose, sometimes a little 

 roughened by some large, feebly-impressed punctures. 



24. (25) Propodeum with some more or less evident, large shallow 



punctures ; basal abdominal segment in strict lateral 

 view very abrupt in front, so that its two faces meet at an 

 angle (rounded off). ... 0. rubopustvlatns, Blackb. 



25. (24) Propodeum dull, but smooth, not punctured ; lateral out- 



line of basal abdominal segment forming an almost even 

 but strong curve from the petiole. 



0. crypternthnts, sji. nov. 



26. (15) Basal segments of^abdomen not red above, nor spotted with 



red at the sides, at most with the apical margin of the 

 basal segment narrowly red. 



27. (60) Males. Antennae 13-jointed, terminal ones modified to 



form a hook. 



28. (29) Second ventral segment largely or entirely red. 



0. dyserythrias, P. 



29. (28) Second ventral segment not red. 



30. (39) Clypelis extremely deeply emarginate, the emargination 



almost semicircular or even deeper. 



