THE CANADIAN ENTOMOLOGIST. 99 



8. Clypeus produced anteriorly and entirely covering the labrum, or the 



latter only slightly visible 9. 



Clypeus not so produced, the disk thickened, convex, the labrum 

 usually large and distinctly visible, rarely partly concealed. 



Head with a prominence above the insertion of the antennie and 

 connected with the clypeus by a carina ; antennae of moderate 

 length ; fifth ventral segment ivith a tooth at each apical angle; 

 pygidium subtriangular, broader at base than long, and longi- 

 tudinally striated ; maxillary palpi 6-jointed ; labial palpi 



4-jointed. (Australia) Zaspilothynnus, Ashm., gen. nov. 



(Type Thynnus Leachiellus, Westw. ) 

 Head anteriorly with two prominences, beneath which are in- 

 serted the antennae; antennae very long; fifth ventral segment 

 without a tooth at the apical angles. 



(Australia) Tachynomyia, Guerin. 



(Type Agriomyia spinola% Guer.) 



9. Clypeus trapezoidal, truncate anteriorly. 



Maxillary palpi 6-jointed, the middle joints the longest ; labial 

 palpi 4-jomted, the first joint the shortest, without a tuft of 

 hairs at apex, joints 2-4 longer, nearly equal in 



length. (Australia) Thynnoides, Guerin. 



(Type T. fulvipes, Guer.) 



Maxillary palpi 6-jointed, the three last joints very long, much 

 longer and slenderer than the basal joints ; labial palpi 

 4-jointed, the first very long, nearly as long as joints 2-4 united, 

 with a tuft of very long hairs at 



apex. (Australia) Pseudaelurus, Ashm., gen. nov. 



(Type Aelurus abdominalis, Guerin.) 



10. Clypeus anteriorly truncate or very slightly arcuate, never emarginate; 



pygidium neither carinate at sides nor truncate at apex it. 



Clypeus anteriorly broadly, shallowly semicircularly emarginate, con- 

 cave or excised ; pygidium squarely truncate at apex and usually 

 carinate at sides, the apical lateral angles acute 15. 



11. Pygidium at apex rounded, without a median incision or emargina- 



tion 12. 



Pygidium at apex rounded, but with a median incision or emargination. 



Abdomen fusiform, maculate; hypopygium with the sides strongly 



rounded or arcuate, and ending in a rather long spine, which is 



