118 HYMENOPTEEA. 



IV. Eyes hare, head scarcely projecting behind them. Antennas inserted in the middle of 

 the face. Antennal grooves distinctly ridged, narrow. Head retreating behind 

 the eyes. Antennal scape narrow, of nearly equal thickness throughout. Pronotum 

 hollow above, a longitudinal suture in the centre. Scutellum narrow at the base. 

 Abdomen narrow at the base, becoming dilated towards the apex ; second and third 

 segments longer than the others. Ovipositor hidden, or exserted. Middle tarsi 

 dilated, setose on the underside. The mesonotum flat or elevated into a hump. 



Antennae 11-jointed, inserted in the middle of the face ; two rings, the first longer 

 than the second, broader at the apex than at the base, second ring a little longer than 

 broad ; first joint of the flagellum longer than the next, second and third subequal, 

 longer than the fourth, which is of the same size as the fifth ; the joints of the club 

 indistinct, its apex acute. Head large, broader than the thorax, slightly convex behind, 

 still more slightly concave in front. Eyes bare, oval ; ocelli in a curved line. Front 

 slightly hollow ; there is no antennal suture. Prothorax transverse, small, the sides 

 rounded. Mesonotum with the sutures well defined. In front of the scutellum is an 

 almost straight transverse carina ; base of scutellum broad, truncated ; apex rounded, 

 broader than the base. Abdomen long, semisessile, tapering towards the apex, which 

 is often cylindrical ; the segments do not differ much in length. Legs slender. Spurs 

 on front tibiae almost obsolete ; on the middle long, stout ; on the posterior short, and 

 two in number. Marginal branch three fourths of the length of the ulna. The 

 following table is a synopsis of the species of Group IV. : — 



1 (16). Mesonotum elevated into a ridge. 



2 (11). Wings smoky, with white fasciae; legs mostly black. 



3 (4) . Antennae entirely testaceous testaceicornis. 



4 (3) . Antennae for the most part black. 



5 (8) . Base of abdomen black ; scape of antennae black, thick, compressed, 



sharp on the lower side. 



6 (7) . Wings hyaline at the base, with a small fuscous spot in the centre of 



the hyaline part ; middle of the flagellum testaceous ; spurs black geniculatus. 



7 (6) . Base of the wings entirely hyaline ; antennae entirely black ; spurs 



white albispina. 



8 (5) . Base of the abdomen white ; scape testaceous, cylindrical, not com- 



pressed. 



9 (10) . Wings with two white spots in middle, hyaline at the base . . . bimaculatus. 



10 (9). Wings with only a narrow curved fascia in the middle ; base smoky . gracilis. 



11 (2). Wings hyaline; legs testaceous. 



12 (13). Thorax mostly red erythrothorax. 



13 (12). Thorax black. 



14(15). Ovipositor as long as the abdomen ; legs testaceous hyalinipennis. 



15 (14). Ovipositor but very shortly projecting ; legs yellow flavipes. 



