64 



47 (48) Second dorsal segment hardly visibly punctured. O. iopteryx. 



48 (47) Second segment with shallow, but conspicuous, puncturation. 



49 (50) Mesonotum very dull, scutellum with sparse and very feeble 



punctures. O. illudens. 



50 (49) Mesonotum not extremely dull, scutellum very distinctly, 



generally rather deeply, though remotely, punctured. 



O. ntontanus. 



51 (46) Propodeum smooth or only with feeble impressions or punc- 



tures; costae of second ventral segment sometimes more or 

 less effaced or indistinct, at least the middle ones. 



52 (53) Mesonotum subrugosely punctured, the punctures of two sizes 



but the smaller ones conspicuous; second segment beneath 

 with a conspicuous triangular depression. O. erro. 



53 (52) Mesonotum with fine sparse puncturation; second ventral seg- 



ment with a narrow and shallow depression, the costae 

 usually more or less effaced at least in the middle of the 

 series. O. unicus. 



54 (45) Wings shining fuscous without blue or steely iridescence. 



55 (56) Large species (about 10 mm. to apex of second abdominal seg- 



ment,) mesonotum subrugosely punctate, the smaller 

 punctures being unusually developed in size as compared 

 with the larger, the latter fine and the whole tending to 

 run into one another. O. paranoias. 



56 (55) Small species, less than the above in length; mesonotum without 



the sculpture described above. 



57 (58) Second dorsal segment in dorsal aspect raised into a conico- 



tuberculate form at about one-fourth of its length from the 

 base. O. pterophaennes. 



58 (57) Second dorsal segment only convex, not conico-tuberculate. 



59 (60) Depression of second ventral segment wider and shallower; 



female with the scutellum much more feebly punctured 

 than the mesonotum. O. dubiosus. 



60 (59) Depression of second ventral segment narrower and deeper; 



female with the punctures of the scutellum not much finer 

 and feebler than those of the mesonotum. O. threnodes 



(ii) SYNOPSIS OF ODYNERUS OF MAUI, MOLOKAI AND LANAI. 



1 (2) Post-scutellum with a distinct raised serrulate or spinulose ridge 



dividing the dorsal and posterior surfaces; second discoidal 

 cell about twice as high at the apex as the third is at the 

 base. O. nigripennis, Holmgr. 



2 (1) Post-scutellum without such a ridge; second discoidal cell gen- 



erally much less than twice as high at the apex as the third 

 is at the base. 



3 (30) Abdomen with red-markings, sometimes only the hind margin 



of the basal segment with a red band, entire or broken; if 

 the abdomen has no red markings, then the mesopleura have 

 a red spot. 



