AMERICAN DIPTERA. ' 20o 



HYBOTIN^. 



18. Third vein simple 19. 



Third vein forked 27. 



19. Anal cell shorter than the second basal 24. 



Anal cell as long as the second basal or longer 20. 



20; Fourth vein forked ; hind femora not incrassate .... 9Ieghy|>eriii>> Loew. 

 Fourth vein simple ; hind femora more or less thickened 21. 



21. Origin of the second vein nearer to the humeral than to the anterior cross-vein. 



Syiieclies Walker. 

 Origin of the second vein not nearer the humeral 22. 



22. "Vein between the first and second basals indistinct Nyu<Iya$« Loew. 



Vein between the first and second basals distinct 23. 



23. Stout, bronzed species with enormously thickened hind femora (Brazilian). 



liactistomyia gen. nov. 

 More slender species of black or blue-black coloration Hy bos Meigen. 



24. Three veins at the apex of the discal cell 25. 



Two veins at the apex of the discal cell 26. 



25. Hind legs lengthened ; tibiae straight E ii til y lie lira Macquart. 



Hind femora thickened ; hind tibife bowed Oedalea Meigen. 



26. Third antennal joint conical, with a terminal bristle liCptopeza Macquart. 

 Third antennal joint oval ; bristle subdorsal Ocydruiiiia Meigen. 



27. Anterior branch of the third vein terminating in the second vein. 



Blepliaroproela Loew. 

 Anterior vein terminating in the costa Bracliystoina Meigen. 



MYTHICOMYIINiE. 



28. No discal cell ; second vein ending in the costa. . Hilaroniorplia Schiner. 

 Discal cell present; second vein ending in the first. 



9Iythiconiyia Coquillett. 



EMPIDIN^. 



29. Discal cell wanting Cyrtoma Meigen. 



Discal cell present 30. 



30. Third vein simple 31. 



Third vein furcate 34. 



31. Proboscis not longer than the head, generally extending straight forward. .32. 

 Proboscis longer than the head; generally directed backwards; antennae 



plainly three-jointed 33. 



32. Eyes of the male separated ; hypopygium minute. 



Iflicrophorns Macquart. 



Eyes of the male contiguous; hypopygium large, pedunculate, and flexed to 



the right Holoclera Schiner. 



33. Face naked Rhaiiipliouiyia Meigen. 



Face provided with bristly hairs Meocota Coquillett. 



34. Proboscis evidently longer than the head 35. 



Proboscis not longer than the head 39. 



TRANS. AM. ENT. SOC, XXVIII. JULY, 1902 



