] 



\ 



\ 



602 FAUNA HAWAIIENSIS 



7. Scape of antennae not much dilated, about twice as long as wide on its broad 



surface 8. 



Scape of antennae strongly dilated, subtriangular, not twice as long as wide ...N. anthracina. 



8. Cheek between the eye and mandible distinct and rather long, plate above the 



clypeus generally narrow and elongate, basal joint of antennae less arched 



beneath N. volcanica. 



Cheek short or very short, plate above the clypeus short ; scape more strongly 

 arched beneath 9. 



9. Process of eighth ventral segment without a longish apical bifurcation ; pubes- 



cence of mesonotum rather long N. difficilis. 



Process of eighth segment with longish bifurcation : pubescence of meso- 

 notum short N. laeta. 



10. Scape of antennae little or not at all dilated, twice as long as wide or more 



than twice, face below the antennae wholly or nearly all yellow, at most 

 the post-clypeal plate and the clypeal sutures being black, the yellow 

 colour always continued back above the line of insertion of the antennae 

 along the inner orbits ; abdomen never conspicuously ferruginous on the 



basal segments 11. 1 



Scape nearly always distinctly, often strongly, dilated, nearly always less than j 



twice as long as wide ; in species, where least dilated, with the hind 

 margin at least strongly curved not very gently curved as in the above 

 group, frequently subtriangular or even subcordiform ; face in front of the 

 antennae rarely largely yellow and with this colour produced behind the 

 antennae along the eye-margins and if so then either the hind margin of 

 the scape is quite strongly rounded or the basal abdominal segments are 

 ferruginous 15. 



11. Face wholly yellow in front of the antennae 12. 



Face not wholly level in front of the antennae, at least part of the post-clypeal 



plate black, the yellow colour produced back along the eye-margins as a 



narrowing vitta N. ohscurata. 



12. Scape of antenna with a yellow mark apically or with a complete yellow line ...N. blackburni. 

 Scape not so marked ; face elongate 13. 



13. Posterior tibiae yellow with a fuscous stain behind N.flainpes. 



Posterior tibiae black at most yellow at the base and apex 14. 



14. Face longer, apical margin of post-clypeal plate much shorter than its sides to 



the antennal fossa N. longiceps. 



Face shorter, apical margin of post-clypeal plate about as long as its side N. finitima. 



15. Abdomen not conspicuously ferruginous on the basal segments; at most (as 



a variation) with a piceous, dull reddish or immature appearance 16. 



Abdomen conspicuously ferruginous basally 35- 



16. Scape of antennae not arched beneath, its lower edge straight or almost 



straight 17. 



Scape distinctly arched beneath 20. 



17. Anterior area of propodeum somewhat coarsely rugose all over N. haleakalae. 



Anterior area at most with short wrinkles in front; species very small 18. 



18. Process of eighth ventral segment not distinctly dilated N. tmitata. 



Process dilated dorsoventrally 19. 



1 9. A very conspicuous deep black median area behind the antennae N. dnmetorum. 



Deep black area not or hardly noticeable N. angustula. 



20. Prothorax with yellow marking 21. 



Prothorax without yellow marking 23. 



