PROCEEDINGS OF THE NATIONAL, MUSEUM. 



VOL. 60. 



10 



Occipital carina obsolete or interrupted dorsally; mesoscutum and scutellum 

 transversely rugose throughout; apical tergite greatly lengthened; (external 

 parasites on wood-boring larvae) Rhyssini. 



Occipital carina complete; mesoscutum and scutellum not transversely rugose, at 

 most the scutum is rugulose; apical tergite only rarely greatly lengthened. . . 1 . 

 Abdomen inserted above, frequently far above, the hind coxae; first tergite 

 narrow throughout; head transverse; occiput narrow, barely concave; temples 

 short and strongly convexly sloping; eyes emarginate within; propodeum 

 nearly straight and horizontal from base to insertion of abdomen; hind coxae, 

 long, slender and nearly uniform in diameter, fig. 9 Labenini. 



11. 



12. 



Fig. 9. — Areolet 

 OF Labena gral- 

 LATOB (Say). 



Fig. 10. — Areolets: a, Tromatobia rufovariata 

 (Cresson); 6, Itoplectis conquisitor (Say); 

 c, Epiurus alboricta (Cresson). 



Not agreeing entirely with above, fig. 10 11. 



Abdomen sessile (not distinctly tapering from spiracles to base and with promi- 

 nent anterior lateral angles), very rarely (Perithous) clavate and slightly com- 

 pressed at apex; areolet usually defined; claws rarely without basal tooth; (ex- 

 ternal parasites on lepidopterous, coleopterous, and hymenopterous larvae and 

 pupae, or in spider egg-sacs), fip. n Ichneumonini. 



Fig. 11.— Sessile first tergite of 

 Perithous pleuraus Cresson. 



Fig. 12. — Petiolate first tergite of Xoe- 

 ides yukonensis (Rohwer). 



Abdomen petiolate (tapering from spiracles to base, and without prominent anterior 

 lateral angles), clavate to subcylindrical and more or less compressed apically; 

 areolet usually wanting; claws without basal tooth; temples broad; (external 

 parasites on wood-boring larvae\ fig. 12 12. 



Mandibles edentate at apex, rarely with a small entodorsal tooth; legs slender, 

 fig. 13 Xoridini. 



Fig. 13.— Mandible of Poemenia Americana (Cresson). 



Mandibles bidentate at apex, the teeth subequal in length; legs stout. 



Odontomerini. 



KKT TO TRIBES. 



1. Abdomen inserted above, frequently far alcove, the hind coxae, first tergite narrow 

 throughout; head transverse; occiput narrow, completely margined, barely 

 concave; temples short and strongly convexly sloping; eyes eraorginate within; 

 propodeum nearly straight and horizontal from base to insert'rm of abdomen; 

 hind coxae long, slender and nearly uniform in diameter; thoracic dort-um not 



at all transversely rugose Labenini. 



Not agreeing entirely with above 2. 



