6o 4 M. W. R. de V. GRAHAM 



times the length of the stigmal vein ; basal vein bare or with one to two hairs. 



All femora mainly black with a metallic tinge . favorinus (Walker) (p. 608) 



- Head and thorax varying from bright blue to bronze-green, bronze, or coppery 



bronze. Postmarginal vein of fore wing slightly to very distinctly shorter 

 than the marginal vein, the latter i-8 to 2 times the length of the stigmal 

 vein ; basal vein with two to ten hairs ....... 9 



g (8) Head and thorax bronze to brassy or coppery bronze, rarely somewhat tinged 

 with olive-greenish in places ; femora sometimes wholly reddish to fulvous, 

 though often more or less infuscate, in which case the fore femora are most 

 heavily so, the hind femora having at most a fuscous patch on their external 

 aspect and a dark interno-dorsal stripe. Scutellum not or hardly longer 

 than broad. Gaster 1 -55 to 1 -75 times as long as broad, as long as or slightly 

 longer than the thorax. Basal vein of fore wing with two to four hairs 



dives (Walker) (p. 608) 



- Head and thorax varying from bright blue to green or bronze-green ; femora 



very variable in colour, the range of coloration much as in dives but some- 

 times all the femora mainly black. Scutellum slightly longer than broad. 

 Gaster 1-7 to 2-4 times as long as broad, somewhat longer than the thorax. 

 Basal vein of fore wing with one to ten hairs . . illudens (Walker) (p. 608) 



10 (5, 6) Combined length of pedicellus and flagellum slightly less than the breadth 



of the head . . . . . . . . . . .11 



- Combined length of pedicellus and flagellum at least slightly greater than the 



breadth of the head .......... 12 



11 (10) Antennal toruli slightly farther from the median ocellus than from the anterior 



margin of the clypeus ; scape (Text-fig. 480) relatively shorter, not 

 reaching above the ocellus ; pronotal collar less sharply margined, usually 

 sharply margined only over about the middle third, sometimes immarginate ; 

 marginal vein of fore wing 2 to 2 • 1 times as long as the stigmal vein ; femora 

 mainly black ; tibiae often more or less broadly infuscate medially ; median 

 area of propodeum uniformly reticulate, the median carina usually straight 

 and sharp ........ epistena (Walker) (p. 610) 



Antennal toruli slightly nearer to the median ocellus than to the anterior 

 margin of the clypeus ; scape relatively longer, reaching slightly above the 

 vertex ; pronotal collar sharply margined except just at the sides ; mar- 

 ginal vein of fore wing 2-2 to 2-5 times as long as the stigmal vein ; femora 

 usually reddish testaceous, sometimes partly or mainly brown ; tibiae 

 pale ; median area of propodeum usually with some strong wrinkles as well as 

 the reticulation, the median carina tending to be irregular, or crossed by 

 one to two crests ...... continua (Walker) (p. 610) 



12 (10) Antennal toruli slightly farther from the median ocellus than from the 



anterior margin of the clypeus ; head in dorsal view (Text-fig. 474) with the 

 frons not protuberant ; legs slender, mid tibia nine to ten times, first segment 

 of mid tarsus 8 to 8-5 times, as long as broad, spur of mid tibia somewhat less 

 than half the length of the first tarsal segment ; marginal vein of fore wing 

 2-2 to 2-5 times as long as the stigmal vein . muscarutn (L.) auctt. (p. 611) 

 Antennal toruli about equidistant from the median ocellus and the anterior 

 margin of the clypeus, or nearer to the ocellus ; head (Text-fig. 473) with 

 the frons somewhat protuberant ; legs stouter, mid tibia 7-5 to 8 times, 

 first segment of mid tarsus six to seven times, as long as broad, spur of mid 

 tibia rather more than half as long as the first tarsal segment ; marginal 

 vein of fore wing 1-7 to 2-2 times as long as the stigmal vein . . . 13 



13 (12) Antennal toruli slightly nearer to the median ocellus than to the anterior 



