98 THE CANADIAN ENTOMOLOGIST. 



Hy]>opygium 3dentate, or trilobed 6. 



Hypopygium 5-dentate, or with 5 spines. 



Clypeus produced and anteriorly truncate or subarcuate, with a 

 short, stout tooth or elevation at the basal lateral angles, near 



the base ot the eyes 4. 



Clypeus anteriorly not much produced, rounded, witJiout a tooth 



at the basal lateral angles 5. 



Abdomen fusiform or ovate, not longer than the head and thorax 

 united, the segments constricted at the sutures ; segments 2-3, or 

 more, with yellow or yellowish-white spots ; first ventral segment 

 with a triangular tooth or elevation near the middle, the sixth with 

 a tooth at the apical angle ; maxillary palpi 6jointed ; labial palpi 



4-jointed. (Australia) Thynnus, Fabricius. 



(Type T. dentatus, Fabr.) 



Abdomen longer than the head and thorax united, the sides nearly 



parallel, the segments more or less constricted at the sutures, black, 



immaculate, the first and sixth ventral segments normal, unarmed \ 



maxillary palpi 6-jointed, the joints short; labial palpi 4-jointed. 



(Australia.) Thynnidea, Ashm., gen. nov. 



(Type Thynnus fumipennis, Westw.) 



Metathorax with a median tooth at apex ; abdomen longer than the 



head and thorax united, cylindrical, the sides parallel, the segments 



constricted at apex, immaculate ; maxillary and labial palpi both 



4-jointed. (Australia) Iswaroides, Ashmead. 



(Type I. Koebelei, Ashm.) 

 Marginal cell at apex pointed or slightly rounded, but never truncate; 



second cubital cell not triangular. . 7. 



Marginal cell at apex truncate ; second cubital cell triangular. 



Clypeus with a median emargination anteriorly; maxillary and 



labial palpi both 3-jointed. (India) Iswara, Westwood. 



(Type I. hiteus, Westw.) 



Hypopygium not narrow, in outline triangular, 3-dentate, the middle 



tooth large, triangular, projecting far beyond the lateral teeth, which 



are usually small 8. 



Hypopygium quite differently shaped, narrower and oblong, as wide 

 or nearly at apex as at base, the sides parallel or nearly, the apex 

 usually briefly tridentate or trilobed, the teeth or lobes equal or 

 nearly, the middle tooth very rarely much longer than the lateral 

 teeth 16. 



