i go M. W. R. de V. GRAHAM 



combined length of pedicellus and flagellum only about i-2 times breadth of 

 head ; funicular segments five and six quadrate . simplex (Thomson) (p. 194) 

 Spur of mid tibia stronger, its length at least slightly greater than the maximum 

 breadth of the tibia. Antennal flagellum with longer hairs, their length at 

 least fully half the breadth of the segments that bear them ... 2 



2 (1) Postspiracular sclerite with a more or less distinct oblique carina which marks 



off a triangular upper area ........ 3 



- Postspiracular sclerite without an oblique carina ..... 4 



3 (2) Either the scutellar frenum has some longitudinal carinulae ; or else the 



stigmal vein (Text-fig. 155) forms a relatively acute angle with the post- 

 marginal vein ........... 18 



Scutellar frenum reticulate, without longitudinal carinulae ; stigmal vein 



forming a relatively less acute angle with the postmarginal vein . . 4 



4 (3) Stigmal vein of fore wing (Text-fig. 155) forming an angle of only 35 to 40 



with the postmarginal vein. Antennal scape not nearly reaching the 

 median ocellus, distinctly expanded above the middle, where there is a large 

 shiny boss on the outer surface ........ 5 



Stigmal vein of fore wing forming a less acute angle with the postmarginal. 

 Antennal scape sometimes reaching the median ocellus, sometimes hardly 

 expanded or with a smaller boss ....... 6 



5 (4) Scutellum, not counting the frenum, and axillae with engraved sculpture ; 



hind coxae bare dorsally ; relatively large species, 2 to 3-5 mm. . . 19 



Scutellum, not counting the frenum, and axillae with at least some of the walls 

 forming their reticulation slightly raised above the general surface ; hind 

 coxae with some hairs upon their dorsal surface . ? saurus (Walker) (p. 197) 



6 (4) Thorax weakly arched dorsally ; in profile the scutellum appears only weakly 



convex. Axillae and scutellum with delicate, engraved reticulation 



geniculatum (Forster) (p. 193) 



- Thorax moderately to strongly arched dorsally ; in profile the scutellum 



appears distinctly, sometimes quite strongly, convex. Axillae and 

 scutellum nearly always having their reticulation at least slightly raised 

 above the general surface ......... 7 



7 (6) Lower edge of mandible (Text-fig. 147) excised in the middle, and with a 



conspicuous lobe at the base. Malar space almost half the length of an 

 eye. Similar in general facies to alpestre (Ruschka) . scaea (Walker) (p. 198) 

 Lower edge of mandible at most shallowly emarginate in the middle, and 

 without a conspicuous lobe at the base. Malar space nearly always rela- 

 tively shorter ........... 8 



8 (7) Ventral opening of oral fossa (cf. Text-fig. 148) large ; the hypostomal 



carinae curving strongly, the greatest distance between them more than one 

 third the breadth of the head ; in a ventral view of the head, the hypostomal 

 carinae are clearly visible even when the maxillae and labium are in situ 9 



- Ventral opening of oral fossa smaller ; hypostomal carinae not curving 



strongly, the greatest distance between them at most one third the breadth 

 of the head ; in a ventral view of the head, the hypostomal carinae lie close 

 to the maxillae and labium, and are not readily seen . . . . 12 



9 (8) Antennal scape distinctly expanded on its front edge above the middle, with a 



large shiny boss which extends nearly half way down the scape ; funicle less 

 slender than in the following species, proximally almost or quite as thick as 

 the pedicellus in profile ..... scoticum (Walker) (p. 196) 



- Antennal scape not expanded above the middle, with only an inconspicuous 



shiny area on its front edge ; funicle slender, especially proximally where 



it is much less stout than the pedicellus ...... 10 



