2 o G. E. J. NIXON 



Tergite i strongly, abruptly narrowed behind, its apical width rarely as much as two 

 thirds its greatest width, usually about half this ; head in a facial view more or less 

 circular, except in lacteoides which has it distinctly triangular but this species has a 

 strong medial keel on the propodeum and a short scape ; inner spur of the hind 

 tibia at least half as long as the hind basitarsus. Old and New World 



merula- group (p. 150) 



- Rarely the vannal lobe with a distinctly concave, fringeless edge and then either the 



head in a facial view is strongly rostriform with long scape and tergite 1 is hardly 

 narrowed behind (lacteus-group) or the inner spur of the hind tibia does not quite 

 reach the middle of the hind basitarsus (grandiculus-group) or there is a faint trace 

 of an areola . . . . . . . . . . . .16 



16 Mouth parts modified and lengthened, the galea fully twice as long as wide and/or the 



head either obviously rostriform or at any rate markedly triangular in facial view. 

 Ovipositor widely exserted ; hypopygium membranous and with numerous 

 lateral creases ; median field of tergite 2 very short and with acute, lateral angle . 1 7 



- Mouth parts simple, the head, in a facial view, never rostriform though it may some- 



times be subtriangular .......... 20 



1 7 Metacarp shorter than the stigma and shorter than its distance from the apex of the 



radial cell. 



Intensely black species with the wings deeply embrowned and the legs dull black 

 throughout ; propodeum rugose with weak medial keel ; vannal lobe beyond its 

 widest part with hardly a trace of a hair-fringe ; hind spurs blackish, the inner one 

 about three quarters as long as the hind basitarsus. Central Europe 



vipio- group (p. 128) 



- Metacarp much longer ; wings only in the S. African caesar-group as dark as this 



and then the hind tibia is predominantly reddish . . . . . . 18 



18 Wings deeply embrowned ; metacarp hardly twice as long as its distance from the 



apex of the radial cell ; tergite 1 strongly narrowed behind ; inner spur of the 

 hind tibia just reaching beyond the middle of the hind basitarsus. S. Africa 



caesar-group (p. 129) 



- Wings hyaline or milky-white ; metacarp at least three times as long as its distance 



from the apex of the radial cell ; tergite 1 not narrowed behind ; inner spur of the 

 hind tibia not, or hardly, longer than the outer one and not reaching middle of the 

 hind basitarsus ............ 19 



19 Face distinctly rostriform (Text-fig. 120) ; labial and maxillary palpus of ordinary 



form ; vannal lobe beyond its widest part markedly concave and here without trace 

 of a hair-fringe. 



Venation mostly colourless ; stigma yellowish with faintly darker border and 

 metacarp still darker ; propodeum without a medial keel. Europe 



lacteus-Qroup (p. 129) 



- Face triangular ; palpi highly modified, black, both pairs being clothed with 



adpressed hairs on posterior side but otherwise bare ; apical segment of both 

 labial and maxillary palpus sharply tapered apically ; vannal lobe very slightly 

 straightened out beyond its widest part but with distinct hair-fringe throughout. 

 Inner spur of the hind tibia slightly shorter than the outer one. Europe 



longipalpis- group (p. 181) 



20 Vannal lobe very obviously concave beyond its widest part and hence becoming 



acuminate distally ; its concave edge completely without hair-fringe. 



Nervellus strongly incurved and much longer than the submediella (Text-fig. 

 180) ; ovipositor sheath about twice as long as the hind tibia. Africa. Oriental 

 Region ........ grandiculus- group (p. 166) 



- Vannal lobe at most with straight edge beyond its widest part and then the edge has 



distinctly projecting hairs or the nervellus is not strongly incurved and is not 



