190 NEMATUS FULVIPES. 



10. The <J, before the apex of the eighth dorsal segment, with a small, 



blunt, more or less awl-shaped process ; the $ with the an- 

 tennae towards the apex scarcely attenuated, almost filiform. 

 Small flies of 3 to 5 mm. in length ; the stigma often pale at 

 the base ; the sheath of the saw often pointed posteriorly ; gall- 

 makers. Pontania, Costa. 

 The eighth dorsal segment with the $ broad, bluntly triangular 

 or hardly elongate before the apex ; the antennae towards the apex 

 distinctly attenuated ; the stigma never pale at the base ; sheath 

 never acuminate ; the body larger. 11. 



11. The last ventral segment at the apex bluntly triangularly elon- 



gated ; sheath normal ; the postei-ior legs simple. 12. 



The last ventral segment of the £ at the apex emarginate, not 



incised ; the sheath very broad, or the hinder tibiae and tarsi 



thickened. 13. 



12. Mesonotum and pleurae shining ; antennae long and slender, usually 



paler beneath the head, seen from the front almost round; the 

 labrum not longly projecting ; the sheath usually very small and 

 weak. Pteronus, Jur. 



Mesonotum and pleurae opaque through a very fine and close punctur- 

 ing ; antennae short, stout, sharply attenuated towards the apex ; 

 head more or less triangular, with a long projecting labrum ; 

 stigma posteriorly longly pointed ; sheath thick and strong. 



Amauronematus, Knw. 



13. Hinder tibiae at the apex and hinder tibiae broadly widened. 



Croesus, Leach. 

 Hinder tibiae and tarsi weakly thickened or simple. 14. 



14. Hinder tibiae and tarsi thickened, the former longitudinally fur- 



rowed. Holcocneme, Knw. 



Hinder tibiae and tarsi simple ; the sheath very thick. 



Nematus, Jur. 



15. Hinder tibiae and tarsi thickened. 14. 

 Hinder legs simple. 16. 



16. Front with distinct pentagonal area. Pachynematus, Knw. 

 Front convex without a pentagonal area. 18. 



17. Pentagonal area more or less distinct ; the last dorsal abdominal 



segment in the <$ with a keel reaching to the apex ; the sheath 

 simple. Lygseonematus, Knw. 



Front concave, or with an indistinct pentagonal area; the keel 

 on the last dorsal segment not reaching to the apex ; the sheath 

 broad, with distinct brush-plates. 18. 



18. Clypeus transverse ; the first transverse cubital nervure absent or 



indistinct. Pristiphora, Latr. 



Clypeus emarginate ; the first transverse cubital nervure distinct. 



Micronematus, Knw. 



Nematus fulvipes (Vol. II, p. 56). 



N. brevis, Htg., is treated by Konow as a distinct 

 species from fulvipes. 



