22 G. E. J. NIXON 



phragma of the scutellum widely visible. Europe. N. America. 



pallipes- group (p. 187) 



- Propodeum on the whole smooth, usually highly polished and always without a 



medial keel. 



Vannal lobe beyond its widest part with a straight or slightly concave edge and 

 here often without a distinct fringe ; tergite (2 + 3) either without a median field 

 or, if one is present, then this is obviously triangular . . . . . 27 



27 Antenna of female extremely short, shorter than the body with the preapical segment 



at most one and a half times longer than wide. 



Highly polished spp. with short, thick legs that are predominantly reddish yellow 

 with the hind femur always of this colour ; inner spur of the hind tibia always 

 distinctly longer than half the hind basitarsus. Africa to Indo-australian region 



congoensis- group (p. 188) 



- Antenna of female normal, longer than the body, except in papilionis and geo- 



metrivorus ; all flagellar segments very obviously elongate ; preapical segment 

 rarely as short as about one and a half times longer than wide. 



Propodeum rather short, its spiracle being separated from the posterior corner by 

 not more than three to four times its own diameter (Text-fig. 225) ; 1st abscissa of 

 the discoideus always very distinctly shorter than the 2nd. Old and New World 

 but mostly Africa ....... formosu s -group (p. 191) 



28 Propodeum strongly to coarsely rugose ; usually showing also a large, posterior, 



flattened surface, bounded above, on each side, by a short, transverse cristula ; in 

 front of each cristula is a short, transverse area that tends to be smoother than the 

 surface elsewhere ; tergite 1 usually widened behind, never narrowed, though its 

 apical corners are often gently, roundly constricted. 



Tergite 2 with or without sulci delimiting a median field but, in any case, this 

 tergite is at least two thirds as long as 3 ; normally, the median field of tergite 2 is 

 strongly transverse, subrectangular and rugose ; if, rarely, it approaches a sub- 

 triangular shape and is virtually smooth, then the sides of the triangle are much 

 shorter than the base. World-wide in distribution . . glotneratus- group (p. 133) 



- If the propodeum is coarsely rugose, then tergite 1 is narrowed behind and obviously 



wedge-shaped or the apical segment of the front tarsus is armed with a con- 

 spicuous, lateral spine (Text-fig. 143) ........ 29 



29 Inner side of the apical margin of the hind tibia with a dense, silky fringe that is 



entirely differentiated from the normal tibial hairs. 



Propodeum short, with a well defined medial keel ; propodeal spiracle enclosed 

 by a keel at least on its posterior side ; phragma of the scutellum hidden ; ovi- 

 positor very short, almost hidden ......... 30 



- Inner side of the apical margin of the hind tibia without such a differentiated fringe 



though it is almost differentiated in some species of the vitripennis-group but in 

 these species the propodeal keel is never enclosed, even partly, by a keel . . 31 



30 Tergite 1 strongly, almost concavely narrowed from awide base to a very narrow apex ; 



the keel that lies posterior to the propodeal spiracle is continued forwards 

 diagonally across the propodeum as far as the anterior extremity of the medial 

 keel ; 1st abscissa of the radius and the transverse cubitus forming a well defined 

 angle at their junction ; posterior ocellus separated from the eye-margin by about 

 twice its own diameter ; vannal lobe with distinct hair-fringe throughout. Java, 

 Philippines ........ siderion- group (p. 138) 



- Tergite 1 virtually parallel-sided to where it turns over and thence narrowed to apex ; 



the keel that lies behind the propodeal spiracle does not extend as far as the 

 anterior extremity of the medial keel ; no angle at the junction of the 1st abscissa 

 of the radius and the transverse cubitus (Text-fig. 149) ; vannal lobe beyond its 



