

606 M. W. R. de V. GRAHAM 



as the stigmal vein ; femora and tibiae yellow, or at most the mid and hind 

 femora reddish to brownish ..... oxygyne (Walker) (p. 607) 



- Antennal scape clearly shorter than an eye, sometimes without a projecting 



carina on its anterior edge ; antennal toruli placed at least slightly nearer 

 to the median ocellus than to the anterior margin of the clypeus ; legs often 

 darker ............ 5 



5 (4) Antennal scape (Text-fig. 483) without a projecting carina, merely with a small 



shiny area (b) ; antennae inserted relatively high, in front view of head the 

 toruli are not or hardly below the level of the middle of the eyes ; gaster 

 with a distinct, often rather large, yellow spot ; legs, apart from the coxae, 

 often wholly or mainly yellow ; marginal vein of fore wing 2 to 2-3 times as 

 long as the stigmal vein ......... 6 



Antennal scape (Text-figs. 484, 485) with a long slightly projecting shiny 

 carina or boss in its upper part ; toruli situated at least slightly below the 

 middle of the eyes ; pale spot of gaster usually indistinct, sometimes absent, 

 rarely large ; legs often darker ; marginal vein of fore wing often shorter 

 relative to the stigmal vein ........ 7 



6 (5) Antennal toruli situated at about level of middle of eyes ; legs, apart from 



coxae, yellow, with hind, less often mid, femora reddish to fuscous 



continua (Walker) (p. 610) 



- Antennal toruli slightly below level of middle of eyes ; femora, especially mid 



and hind ones, often more or less infuscate ; tibiae sometimes with a fuscous 

 band ........ epistena (Walker) (p. 610) 



7 (5) Head in exact dorsal view (Text-fig. 481) only i-8 to 1-9 times as broad as its 



maximum length, with the frons projecting in an even curve and the 

 antennal toruli clearly visible. Flagellum rather slender, hardly as stout 

 as the pedicellus in dorsal view ; combined length of pedicellus and flagellum 

 1 -7 to i-8 times the breadth of the head ; funicular segments relatively long, 

 the first 2-5 to 3 times as long as broad ; carina of scape (Text-fig. 484) 

 extending over nearly two-thirds of its length . fontanus (Walker) (p. 609) 



- Head in dorsal view (Text-fig. 482) 2 to 2-2 times as broad as its maximum 



length, the frons not projecting medially. Flagellum sometimes relatively 

 shorter and stouter, or with relatively shorter funicular segments ; carina 

 of scape usually extending over about half its length .... 8 



8 (7) Combined length of pedicellus and flagellum 1-7 to r-8 times the breadth of 



the head ; flagellum slender, not or hardly stouter than the pedicellus when 

 the latter is seen in dorsal view ; funicular segments relatively long, the 

 first 2-5 to 3 times, sixth i-6 to i-8 times, as long as broad ... 9 



- Either the combined length of pedicellus and flagellum is only 1 -4 to 1 -6 times 



the breadth of the head, or the funicular segments are relatively shorter, the 



first i-6 to 2-5 times, sixth 1-2 to i-6 times, as long as broad . . . 11 



9 (8) Length of antennal scape only about equal to the transverse diameter of an 



eye ; smaller species, 2 to 3-4 mm. 



Head, text-fig. 482 ...... favorinus (Walker) (p. 608) 



Length of antennal scape at least slightly greater than the transverse diameter 



of an eye ; larger species, 3-2 to 4-5 mm. ..... 10 



10 (9) Hind femora mainly fuscous to black, mid femora more or less so beneath ; 

 head, including occipital surface, dark blue, or partly bluish ; postmarginal 

 vein of fore wing as long as or slightly longer than the marginal vein 



laticeps (Walker) (p. 607) 



- Femora fulvous to reddish, the fore femora sometimes more or less infuscate ; 



head varied with greenish and bronze, the occipital surface sometimes bluish ; 



