THE CANA.DIAN ENTOMOLOGIST. 285 



6. Middle mesothoracic lobe medially more or less depressed and xvith 



a distinct median grooved line or furrow ; marginal cell in hind 



wings pointed at apex, but with a distinct appendage 8. 



Middle mesothoracic lobe convex, without a distinct median grooved 

 line, with a more or less median carina posteriorly ; if this groove is 

 at all present, only slightly indicated anteriorly ; marginal cell in 

 hind wings pointed at apex, but without a distinct appendage. 



Male characters 7- 



Female characters. 



Antennae rather widely separated at base, with a convex promi- 

 nence between, which is margined superiorly ; last dorsal 

 abdominal segment short, rounded at apex . . Pontania, Costa. 



7. Last dorsal abdominal segment with a small blunt, more or less awl- 



shaped, projection Pontania, Costa. 



8. Male characters 9. 



Female characters. 



Frontal area more or less well defined ; mesonotimi and pleura 

 shining, smooth, or at most sparsely punctate ; last dorsal ab- 

 dominal segment not long, squarely truncate or very slightly 

 rounded at apex. 



Last ventral segment at apex without a median sinus or incision. 



Legs normal, the hind tarsi not thickened. .Pteronus, Jurine. 



Legs with the hind tibiae and tarsi more or less thickened, 



the former longitudinally sulcate. . . Holcocnema, Konow. 



Last ventral segment at apex ivith a median sinus or 



incision Nematus, Jurine. 



Frontal area wanting ; mesonotum and pleura opaque, with very 

 dense and fine punctures ; last dorsal abdominal segment almost 

 as long as wide, at apex rounded or triangularly produced ; last 

 ventral segment triangularly produced . . Amauronematus, Konow. 



9. Last ventral segment at apex obtusely, triangularly produced or trun- 



cate. 



Last dorsal abdominal segment at apex medially, with a rounded 



or truncate projection Pteronus, Jurine. 



Last dorsal abdominal segment at apex truncate, without a pro- 

 jection. 



First dorsal abdominal segment not deeply incised ; terminal 

 ventral plate only about twice as long as wide ; frontal 

 area more or less distinct. 



