THE CANADIAN ENTOMOLOGIST. 105 



34. Head subquadrate or subglobose 35. 



Head large, obtrapezoidal, the temples abnormally broad. 



Abdomen oblong oval, the second dorsal segment with three or 

 four transverse folds or carina; ; pygidium long oval, longi- 

 tudinally striate; labrum longly ciliated; maxillary palpi minute, 

 2-jointed ; labial palpi 4-jointed, the last joint as long as joints 

 1-3 united. (Australia.) Cephalothynnus, Aslim. 



35. Head subquadrate or subglobose, the hind angles rounded, the 



temples about four times the width of the eye 36. 



Head almost quadrate, only a little wider than long, the temples only 

 about twice the width of the eye. 



Abdomen large, oblong-oval, the second dorsal segment with 

 about five transverse carinas ; pygidium long, ellipzoidal, very 

 slightly narrowed at the middle and longitudinally striate ; 

 labrum hardly visible, ciliate; maxillary palpi minute, 2-jointed; 

 labial palpi short, 3-jointed, the second joint the longest and 

 thickest (?) Thynnidea, Ashm. 



36. Metathorax with the disk of the oblique truncation flat but not 



concave 37. 



Metathorax with the disk of the oblique truncation concave or sub- 

 concave. 



Abdomen large, oblong-oval, the second dorsal segment coarsely 

 rugulose,\vith two transverse folds or carinse at apex; pygidium 

 longitudinally rugulose Elaphroptera, Guerin. 



37. Metathorax without a hump-like elevation at base just behind the 



scutellum 38. 



Metathorax with a hump-like elevation at base just behind the 

 scutellum. 



Second abdominal segment with a transverse fold or carina near 

 base and another near apex, the intermediate space very 

 coarsely rugulose; pygidium oblong-oval, finely, longitudinally 

 aciculated towards apex Pycnothynnus, Ashm. 



38. Metathorax obliquely truncate from the base, without a distinct 



metanotum , 39. 



Metathorax with a short but distinct metanotum, trapezoidal, the 

 truncation abrupt, perpendicular ; abdomen with a depression near 

 apex and a delicate transverse carina just before apex; the 

 depression finely coriaceous; second segment with a depression 



