IV CONTENTS 



Subfamily Ephialtinae — Continued Page 



4. Tribe Theroniini 350 



Key to the Nearctic genera of Theroniini. 351 



1. Genus Theronia 351 



2. Genus Delomerista 362 



3. Genus Pseudorhyssa 373 



5. Tribe Poemeniini 375 



Key to the Nearctic genera of Poemeniini 376 



1. Genus Poemenia 376 



2. Genus Podoschistus 387 



3. Genus Neoxorides 389 



6. Tribe Rhyssini 395 



Key to the Nearctic genera of Rhyssini 395 



1. Genus Rhyssa 396 



2. Genus Rhyssella 409 



3. Genus Epirhyssa 413 



4. Genus Megarhyssa 415 



Subfamily Xoridinae 436 



Key to the tribes of Xoridinae 437 



1. Tribe Xoridini 437 



Key to the genera of Xoridini 438 



1. Genus Ischnoceros 438 



2. Genus Aplomerus 439 



3. Genus Odontocolon 448 



4. Genus Xorides 489 



Key to the subgenera of Xorides 491 



Key to the Nearctic subgenera, species groups, and species of 



Xorides 492 



1. Subgenus Gonophonus 494 



2. Subgenus Cyanoxorides 494 



3. Subgenus Epixorides 494 



4. Subgenus Gonioprymnus 495 



5. Subgenus Moansa 495 



6. Subgenus Moerophora 495 



7. Subgenus Exomus 496 



8. Subgenus Periceros 501 



9. Subgenus Xorides 501 



10. Subgenus Pyramirhyssa 530 



2. Tribe Labenini 530 



1. Genus Labena 531 



3. Tribe Labiini 537 



1. Genus Grotea 538 



4. Tribe Poecilocrj'ptini 541 



5. Tribe Brachycyrtini 541 



1. Genus Brachycyrtus 542 



Subfamily Acaenitinae 544 



Key to the Nearctic genera of Acaenitinae 545 



1. Genus Coleocentrus 546 



2. Genus Mesoclistus 560 



3. Genus Aroles 561 



4. Genus Spilopteron 568 



5. Genus Yezoceryx 578 



Figures 580 



Indices 635 



