12S Syrphidae. 



9. Third antennal joint paler or darker brownish; eye- 



margins very narrow; thorax finely punctate 6. scutellata. 



— Third antennal joint orange; eye-margins a little 

 broader; thorax a little more coarsely punctate. ... 7. soror. 



10. Epistoma with hairs on the sides 11. 



— Epistoma without hairs 15. 



11. No thoracai or scutellar marginal bristles 12. 



— Thoracai and scutellar marginal bristles present 13, 



12. Pubescence very long, tricolorous on abdomen; wings 

 with a more or less distinct band or blotch on the 



middle 10. illustrata. 



— Pubescence rather short, unicolorous on abdomen; 



wings without band or blotch 14. intonsa. 



13. Legs black 11. variabilis. 



— Legs more or less yellowish 14. 



14. Frons not large and swollen; epistoma not specially 

 broad ; antennæ dark ; scutellar marginal bristles short 



and inconspicuous; tibiæ not pale at apex 12. honesta. 



— Frons large and swollen; epistoma broad, twice as 

 broad as the diameter of the eye; antennæ more or 

 less reddish; scutellar marginal bristles long, though 

 inconspicuous; anterior tibiæ a little pale at apex. . 13. frontalis. 



15. Scutellum without marginal bristles, and likewise post- 



alar callus (except canicularis) 16. 



— Scutellum with marginal bristles, when indistinct at 



all events postalar callus with bristles 19. 



16. Eyes hairy only on the upper part; arista distinctly 

 pubescent; thorax with some short bristles at the 



sides; antennæ brown or brownish red 15. canicularis. 



— Eyes hairy all over; arista almost bare; no bristles 



on thorax 17. 



17. Antennæ brown or blackish brown 16. grossa. 



— Antennæ orange 18. 



18. Tibiæ quite yellow, at most the anterior tibiæ with 

 indications of rings; frons yellow-haired 17. albipila. 



— All tibiæ with distinct, blackish rings; frons black- 



haired 18. chloris. 



19. Legs quite black or with only middle joints of anterior 



tarsi pale 20. 



— Legs more pale (in carhonaria only anterior knees 

 rather obscurely) 21. 



20. Legs quite black 23. impressa. 



— Middle joints of anterior tarsi pale 24. albitarsis. 



21. Legs only slightly pale, hind tibiæ quite or almost 



quite black and tarsi all black 22. 



— Legs generally paler, hind tibiæ generally not quite 

 black, tarsi more or less pale, at least middle tarsi 

 somewhat pale (in mutabilis hind tibiæ black and 

 middle tarsi sometimes rather obscurely pale) 24. 



22. Eye-hairs pale; epistoma not much protruding or 



