2b6 [November, 



8 (9) Propoduuiu rugose ur densely rugosely puuclate. 



8a (Hb) Face with a red line entering the sinus of the eye, mesothorax with red 



lilies O. homoeophaiies, sp. nov. 



86 (8a) Face without sucli a line, mesotliorax entirely black... 



0. eucharis, sp. nov. 

 Propodeum nearly smooth, with only feeble punctures... 



O. oahuensis, D. T. 

 No red markings on thorax or abdomen, rarely some of the abdominal 



segments have an indistinct testaceous margin. 

 One or more entire yellow or white bands on the abdomen (tiiorax often 



with yellow markings). 

 Mandibles in both sexes entirely or almost entirely red {S with the 

 clypeus extremely deeply emarginate at apex, that of the ? distinctly 

 but much less deeply) O. xeroiihilus, sp. nov. 



13 (12) Mandibles at most red or piceous on their apical half, generally for the 



most part black. Clypeus of S never extremely deeply emai'ginate. 



14 (15) Second ventral segment behind the costse witli a distinct, though not 



deep depression, which is widely triangular. ( <? with the clypeus 

 rather deeply emarginate, and the scape of the antennae entirely yel- 

 low in front ; '^ with a yellow spot on each side of the propodeum 



near the insertion of the abdomen) 0. nautarum, Sauss. 



( $ = O. nesotrephes, P.) 



15 (14) Second ventral segment behind the costte often flattened but without a 



distinct wide triangular depression, if a depression is present it is 

 very narrow, sublinear or linear. ( $ clypeus never deeply emarginate, 

 often with an apical impression giving an appearance of a stronger 

 emargination than is reaily present ; scape of antennte very rarely 

 entirely yellow in front, often all black ; $ without yellow spots 

 laterally on the propodeum near the insertion of abdomen). 



16 (17) Second ventral segment abruptly though not greatly raised from the 



apices of the costse, depression feeble and linear for the most part ; 

 wings fuscous, shining, but without blue iridescence... 



O. ivaianaeanus, Perk. 



var. =^ fiosculus, Perk. 



17 (16) Second ventral segment flattened or faintly convex behind costse, never 



abruptly raised from their apices, wings often with a distinct blue 

 iridescence. 



18 (19) Costse of second ventral segment very short, shorter than the tumid 



basal part of the segment anterior to them ... O. accslogaster, Perk. 



19 (18) Costse not very short, the middle ones generally long and not shorter 



than the basal divisiot* of the segment. 



20 (23) Wings with more or less distinct blue iridescence, clypeus of $ Jiearly 



always and the thorax often marked with yellow. 



21 (22) Maxillary palpi of $ very long and beautifully fringed with long hairs ; 



$ , front of head rather remotely punctured, maxillary palpi more 



developed Pseudopteroeheilus (gen. nov.). 



relictus, Perk. 

 (Type species, Udynerus pterocheiloides, Perk.). 



