OF WASHINGTON. 27 



Abdominal petiole wider than long, or at the most not longer 



than wide Dorylus Fabricins 



(Type, Vespa helvolus Linne) 



9. Mesonotal suture obsolete or very indistinct 10 



Mesonotal suture very distinct or indicated by a constriction 13 



10. Abdomen normal, not constricted between each segment n 



Abdomen abnormal, constricted between each segment; pygidium 



impressed or forked; antennae ii-jointed (rarely 12-jointed), 



Sphinctomyrmex Mayr 

 (Type, Typhlopone stolli Mayr) 



11. Antennae n or 12-jointed 12 



Antennae lo-jointed. 



Head very large, the clypeus prominent Shuckardia Emery 



(Type, Alaopone abeillei Andre) 



12. Antennae 12-jointed, gradually thickened towards apex; head not 



much longer than wide; maxillary palpi 2-, labial palpi 3-jointed; 

 mandibles curved, with a strong triangular tooth near base 



within Cheliomyrmex Mayr 



(Type, C. Nortofti Mayr) 

 Antennae 12-jointed; head about twice as long as wide, 



Probolomyrmex Mayr 

 (Type, P. filiformis Mayr) 



13. Antennae 12-jointed, gradually thickened towards apex; clypeus very 



narrow, transverse; maxillary palpi 2-, labial palpi 3-jointed, 



Cheliomyrmex Mayr 

 (Type, C. nortoni Mayr) 



14. Head bilobed; petiole transverse, obtuse above and produced into 



acute angles behind. 



Thorax trilobed 15 



Thorax not trilobed 16 



15. Thorax trilobed with a distinct constriction between the lobes, the 



metathoracic lobe the narrowest; mandibles long acute; abdomen 

 terminating in a peculiar plate which has a deep, narrow, median 



emargination at apical half Anomma Shuckard 



Thorax trilobed but without a distinct constriction between the 

 lobes, although the lobes are distinctly separated or indicated by 

 faint sutures above; hypopygium not narrow, broadly emarginate 

 at apex Dorylus Fabricius 



16. Thorax a parallelogram, a little more than twice as long as wide, 



with a slight lateral constriction at the middle, the lobes closely 

 united, not indicated by sutures above; hypopygium narrow, the 

 sides parallel, deeply forked at apex Dichthadia Gerstacker 



17. Front wings with two cubital cells, the stigma narrow, lanceolate. 



Abdominal petioles wider than long, convex anteriorly, but trun 

 cate or emarginate posteriorly; first two joints of flagellum 

 nearly equal J 



