THE CANADIAN ENTOMOLOGIST. 97 



dilated into a broad margin at apex, or trumpet-shaped, the former 



often striate or coarsely sculptured Subfamily I., Thynninoe. 



Metathorax not very short ; abdomen smooth, the second dorsal 

 segment without transverse folds or caringe, the pygidium and hypo- 

 pygium normal, not modified in any 

 way Subfamily III., Rhagigasterin^e. 



4. Hypopygium armed with one or more spines or teeth or trilobed. . . 5. 

 Hypopygium unartned, at apex truncate or rounded 9. 



5. Thorax elongate ; front wings with radial and cubital cells 6. 



Thorax rounded; front wings without radial and cubital cells 9. 



6. First transverse cubitus distinct, with an appendage 7. 



First transverse cubitus wanting, or if present, a/zV/^^?;;;/ an appendage . . 8. 



7. Mandibles bidentate ... .Subfamily I., Thynninse. 



Mandibles tridentate Subfamily III., Rhagigasteriuii^. 



S. Hypopygium produced at apex into a long aculeus which curves 



upwards Subfamily II., Methocinse. 



Hypopygium armed with a long aculeus which curves upwards, but 



that originates before the apex Subfamily III., Rhagigasterinse. 



9. Mandibles bidendate Subfamily I., Thynninaa. 



Mandibles tridentate Subfamily III., Rhagigasterinas. 



Subfamily I. — Thynninaj. 

 The males in this group show a wonderful difference in the structure 

 of the mouth-parts and in their genitalia, which, in time, will enable 

 the group to be divided into four or more tribes, namely, Thyimini, 

 Myrmecodini, Scotaenini, Ai?iblysomini, etc. ; but this had better not be 

 done until more of the forms, in both sexes, are known. 



Table of Genera. 

 Males 1. 



Females 29. 



1. Hypopygium armed, ending in a single triangular tooth or spine, or 



tridentate or trilobed ; sometimes 5-dentate, a small tooth on each 

 side at base in addition to the apical teeth ; sometimes oblong, 



narrowed, tridentate, or trilobed at apex • 2. 



Hypopygium u?iariiied, truncate or rounded at apex 20. 



2. Hypopygium at least tridentate or trilobed, sometimes 5-dentate. . .3. 

 Hypopygium ending in a large triangular tooth or single spine, rarely 



with indications of a lobe at the basal angles of same, the lateral 

 margins sometimes arcuate or rounded 10, 



