388 



XORTH AMERICAN DIPTERA 



13. Anterior tibiae without a short, rectangular apical spine below 14 



Anterior tibiae with a short, stout, rectangular spine at apex of ventral 



surface *Acanthocnema Becker 



14. Anteroventral surface of the anterior femora and tibiae without stout 



bristles, the front tibiae rarely with a single bristle on this surface. 15 

 Anteroventral surface of the anterior femora and tibiae with stout 

 bristles Norellia Desvoidy 



15. Prothoracic bristle always, the stigmatic usually, present 16 



Prothoracic and stigmatic bristles absent 28 



16. Palpi long and slender, armed at the apex with a long, outstanding 



bristle 17 



Palpi more or less broadened, without an outstanding bristle 20 



17. Third vein not sinuate 18 



Third vein rather strongly sinuate Scoliaphleps Becker 



18. Stigmatal bristle weak or hair-like, usually absent 19 



Stigmatal bristle strong (46, 60) .Cordilura Fallen 



19. Eyes round Neogymnomera Malloch 



Eyes with a slight emargination on the lower posterior half 36 



* Curran, 1929, Can. Ent., Ixi. p. 132. 



Muscidse I. — 1, Helina lucoriim ; 2, Schcenomjza chcrysostoma ; 3, Limosia; 4. 5. Lasiops 

 spiniger; 6, Phyllogaster cordjluroides ; 7, 8. Fannia ; 9, Ophyra jenescens; 10, Helina; 11, 

 Spilaria; 12, Pseudoliinnophora ; 13, Pseudolimnophora, antenna: 14, 15, Lispe; 16. Limnophora. 



