67 



42 (41) Frontal spot and tegulae not red. 



43 (46) Apical margins of two basal abdominal segments yellow or 



whitish and either the clypeus is only lightly emarginate, or 

 if rather strongly then the second segment of the abdomen 

 is somewhat strongly and abruptly raised from the base; 

 in the male at least into a conical tuberculate form. 



44 (45) Second segment of abdomen above simple, beneath not 



abruptly raised from the apices of the costae. 



O. nubicola, P. 



45 (44) Second segment above raised from the base; beneath abruptly 



elevated from the apices of the costae. O. nivicola, P. 



46 (43) Abdomen often black or with one yellow band, if with two 



bands then the clypeus is deeply or very deeply emarginate 

 and the second dorsal segment of the abdomen is simply 

 convex, never abruptly raised from the base into a sub- 

 tuberculate conical form. 



47 (52) Second ventral segment flat or nearly so behind the costae and 



without any depression, the basal part tumid and either the 

 costae are extremely short compared with the basal part, 

 or the apex of the clypeus and mandibles are both red. 



48 (49) Apex of clypeus and mandibles both red. O: eupteryx, P. 



49 (48) Apex of clypeus not red. 



50 (51) Propodeum shining. O. brevicostatus, P.* 



51 (50) Propodeum dull (middle tibiae without a calcar). 



Nesodynerus paractias, sp. nov. 



52 (47) Second ventral segment in most species with a more or less 



distinct depression behind the costae, which are never 

 excessively short, nor is the basal part very largely devel- 

 oped and tumid, nor is the apex of the clypeus ever red. 



53 (70) Males; antennae thirteen-jointed, terminal joints modified into 



a hook. 



54 (61) Apex of clypeus rather deeply or very deeply emarginate, in 



the first case yellow or yellow-spotted. 



55 (56) Mesothoracic puncturation nearly or entirely effaced. 



O. sociabilis, P. 



56 (55) Mesothoracic punctures always distinct, if shallow. 



57 (60) Clypeus extremely deeply emarginate, the emargination not 



less than a semi-circle. 



58 (59) Mandibles red. O. molokaiensis , P. 



59 (58) Mandibles dark. O. smithii, D. T. 



60 (57) Emargination of apex of clypeus less than a semi-circle (head 



above the antennae with somewhat remote puncturation). 



O. insulicola, Bl. 



* It is very probable that O. brevicostatus and possible that O. eupteryx 

 belong to the genus Nesodynerus, the unique types of these species in the 

 British Museum not having been examined for the essential generic 

 character. 



