THE CANADIAN ENTOMOLOGIST. 207 



Table of Tribes. 



Second cubital cell not petiolate, although often narrowed or angulate 

 above ; mandibles most frequently long, acute, and when united forming 

 a long beak, the teeth lateral. 



Abdomen distinctly petiolate Tribe I. — Eumenini. 



Abdomen sessile or subsessile, never distinctly 



petiolate Tribe II. — Odynerini. 



Second cubital cell distinctly petiolate Tribe III. — Alastorini. 



Tribe I. — Eumenini. 



This tribe is separated from the Alastorini by the non-petiolate 

 second cubital cell, and from the Odynerini by the distinctly petiolate 

 abdomen, the species being, as a rule, narrower, more elongate, and less 

 robust. 



Table of Genera. 



i. Maxillary palpi 3-jointed ; antennae inserted on the middle of the 



face 2. 



Maxillary palpi 6 jointed 3. 



2. Mandibles rather long and narrow, with blunt teeth on the inner 



margin ; anterior angles of pronotum not 



acute Montezumia, Saussure. 



(Type M. rufidentata, Sauss.) 



3. Labial palpi 4-jointed ; second abdominal segment not constricted 



into a petiole at base, or, at the most, subpetiolate ; clypeus longer 



than wide 4- 



Labial palpi 3-jointed ; second abdominal segment constricted into a 

 petiole at base ; head large, quadrate, the clypeus wider than 



long Zethus Fabricius. 



(Type Vespa coeruleopennis, Fabr.) 



4. Mandibles at apex 3- or 4-dentate 5. 



Mandibles at apex bidentate 6. 



5. Mandibles long, 4-dentate, the teeth, however, usually indistinct ; 



clypeus at apex usually truncate ; petiole long ; third cubital cell 



irregular Eumenes, Fabricius. 



(Type Vespa coarctata, Linne'.) 



Mandibles 3-dentate, the teeth acute ; clypeus at apex bidentate ; 



petiole long, subclavate, a little longer than the thorax ; third 



