146 Orthorrhapha brachycera. 



balloon, mentioned above under Empis, it is also possible, that we 

 have here to do with a particular structure. 



The genus comprises about 110 species from the palæarctic 

 region: 26 have hitherto been found in Denmark; of these three are 

 here described as new, the total number of palæarctic species thus 

 increasing to about 113. 



Tahle of Species. 



1. Legs quite black or blackish brown, sometimes greyish 

 pruinose (with or without lighter knees) 2. 



— Legs not quite black or blackish brown, either yellow, 



or at all events the front legs more or less yellow .... 21. 



2. Halteres dark or black 3. 



— Halteres yellow 15. 



3. Dorsocentral and acrostichal bristles very short, pluri- 

 serial; scutellar bristles 6 — 10; abdomen and legs 

 yellow-haired 10. maura. 



— Dorsocentral bristles uniserial, at most a little irregularly 

 biserial; abdomen and legs dark-haired 4. 



4. Acrostichal bristles quadriserial or tri- to quadriserial . . . 5. 



— Acrostichal bristles biserial 9. 



5. Scutellar brislles 6 — 8 11. interstincta. 



— Scutellar bristles 4 6. 



6. Thorax and abdomen black, shining 7. 



— Thorax and abdomen dull black, or thorax blackish 

 brown, abdomen slightly shining 8. 



7. Dorsocentral and acrostichal bristles not very short, 

 the former long behind, the latter not distinctly 

 quadriserial in front; discai cell not specially long; 



hind tibiæ in the female simple I. cornicula. 



— Dorsocentral and acrostichal bristles very short, the 

 former not long behind, the latter quite quadriserial ; 

 discai cell rather long; hind tibiæ in the female 



thickened in the apical half 4. discoidalis. 



8. Thorax black, thoracic bristles rather long; abdomen 

 dull; wings generally blackish; hind tibiæ in the 



female very broad and curved 8. nigrina. 



— Thorax blackish brown; abdomen a little shining; 

 wings not blackish; hind tibiæ in the female less 



broad and less curved 5. quadrifaria. 



9. Discai cell unusually long and attenuated outwards; 



front metatarsi in the male simple 26. minuta. 



— Discai cell of common shape; front metatarsi in the 



male thickened 10. 



10. Thorax dark brown with four more or less distinct 



stripes 17. histriata. 



— Thorax not with four stripes 11. 



11. Thorax much shining, abdomen quite dull; front 



metatarsi in the male somewhat quadratic 6. chorica. 



