1891. J 325 



and legs, from the presence or absence of diseal setfc on the central 

 abdominal rings, from variations in the length of the antenna) (those 

 of the male are often longer than those of the female), from the 

 degree of extension of the fronto-orbital bristles on the cheeks, and 

 other minor points of structure. 



1 (10) Palpi black. 



2 (3) Scutellum partly red 1. vulcraris,^}^. 



3 (2) Scutellum black or grey. 



4 (5) Fronto-orbital bristles extending to near the bottom of the cheeks... 



2. amplico7'nis, Ztt. 



5 (4) Fronto-orbital bristles not extending below the middle of the cheeks. 



6 (9) Apical cross vein of wings nearly straight, and first posterior cell always a 



little open. 



7 (8) Arista thickened to the middle 3. Jiinhriata, Mgn. 



8 (7) Arista long, slender, and only thickened at the base... 4. mutabilis,^\n. 



9 (6) Apical cross vein much curved, and first posterior cell nearly or quite 



closed 5. dtibia, Fin. 



10 (1) Palpi red or partly red. 



11 (26) Legs wholly or partly red or yellow. 



12 (13) Legs wholly yellow 6. vetula,MgT\. 



13 (12) Femora black, but tibiae yellow or red. 



14 (15) Fronto-orbital bristles in a double row in the males. . . 7. biserialis, Mcq. 



15 (14) Fronto-orbital bristles in a single row in the males. 



16 (21) Sides of the abdomen mostly marked with red. 



17 (20) Middle abdominal segments without diseal setae. 



18 (19) Frontal stripe as wide or wider than the sides of the frontalia... 



8. lucorum, Sign. 



19 (18) Frontal stripe narrower than the sides of the frontalia... 9. gnava,'Mg\\. 



20 (17) Middle abdominal segments armed with diseal setffi... 10. chelonicB,'R\\d. 



21 (16) Sides of the abdomen without red marks. 



22 Colour whitish or yellowish-grey. 



23 (25) Scutellum quite red 11. leucopha:a,'Mgn. 



24 (23) Scutellum with only the tip red 12. albicans, 'E\n. 



25 (23) Scutellum black 13. perturbans, Ztt. 



26 (11) Legs black. 



27 (42) Scutellum red or partly red. 



28 (31) Middle abdominal segments without diseal setse. 



29 (30) Thorax indistinctly marked, scutellum all red 14. fauna, Mgn. 



30 (29) Thorax distinctly striped, scutellum only red at the tip... 



15. acronyctartim, Mcq. 



31 (28) Middle abdominal segments with diseal seta;. 



32 (35) Abdomen with apes red. 



33 (34) Wings with little cross vein clouded 16. rvjicauda, Zit. 



34 (33) Wings with cross veins clear 11. apicalis, Mgw. 



35 (32) Abdomen with apex black. 



36(37) Palpi with tips only red 1%. lota, Mgn. 



37 (36) Palpi wholly red or yellow. 



