210 THE CANADIAN ENTOMOLOGIST. 



12. Maxillary palpi 3- or 4-jointed 13. 



Maxillary palpi 5-jointed. 



Labial palpi 3-jointed Monobia, Saussure. 



(Type Vespa quadridens, L.) 



Labial palpi 4-jointed Hypagris, Saussure. 



(Type H. abdominalis, Sauss.) 



13. Maxillary palpi 4-jointed 14. 



Maxillary palpi 3-jointed 15. 



14. Metathorax quadridentate . Antagris, Saussure. 



(Type A. aequatorialis, Sauss.) 



Metathorax concave, bidentate or bispinose Paragris, Saussure. 



(Type P. Humbertii, Sauss.) 



15. Metathorax short, impressed or subconcave posteriorly, the post- 



scutellum often broadly but not deeply emarginate or impressed at 

 apex ; mesonotum without distinct furrows, at the most represented 

 by two delicately impressed abbreviated lines posteriorly; mandibles 



long, acute Synagris, Latreille. 



(Type Vespa cornuta, L.) 



Tribe III. — Alastorini. 



This tribe is separated from the two previously-defined tribes by the 

 venation of the front wings, the second cubital cell being distinctly 

 petiolate. 



Table of Genera. 



1 . Abdomen sessile or subsessile 2. 



Abdomen distinctly petiolate 3. 



2. Mandibles long, acute, bluntly dentate within; maxillary palpi 



6-jointed ; labial palpi long, 4-jointed, the last joint minute. 

 First abdominal segment without a transverse suture or fur- 

 row Alastor, Lepeletier. 



(Type A. atropos, Lepel.) 

 First abdominal segment with a transverse suture or fur- 

 row . Alastoroides, Saussure. 



(Type Alastor clotho, Lepel.) 



3. Form slender ; thorax elongate Smithia, Saussure. 



(Type S. Natalensis, Sauss.) 



