12 NORTH AMERICAN DIPTERA. 



3. Anteniiie bead-like, tlie joints verticillate. ..... 4 



Antennas cylindrical, the joints approximated, not petiolatc, and pro- 

 vided with short, close hair. . . . . . . .11 



4. The third longitudinal vein terminates in the costa before the tip of the 



wing. . . . {Dasijneura) Ckcidomyia Loew (non Moigen). 

 The third vein terminates at or beyond the tip of the wing. . 5 



5. Thorax highly arched, hood-like, over the liead. Hohmomvia Loew. 

 Thorax only moderately arched ; wings irridescent. ... 



6. Wings with but three longitudinal veins, the first, third and fifth. 7 

 Wings apparently with four longitudinal veins, the first, third and two 



in place of the fifth, the furcation taking place so near the root of 

 the wing as to give the ax)pearance of two longitudinal veins. 10 



7. The anterior cross-vein, that is the vein arising at the root of the wing 



and connecting with the third nearly where it arises from the first, is 

 curved /-shaped. ......... 8 



The anterior cross- vein is nearly straight, appearing as the beginning 

 of the third vein. ......... 



8. Wings very long and narrow. . . . Colpodia Winnertz. 

 Wings not more than three times as long as wide. Epidosis Loew. 



9. Joints of the antennas petiolate, in the nuile usually with two bead-like 



swellings on each joint. 



{Cecidomi/ia Moigen non Loew) Diplosis Loew. 



Joints not petiolatcd, or at the most the males with a single bead-like 



swelling on each joint. ..... I^ikiiiza Loew. 



10. Palpi large, with the last joint elongate; anterior cross-vein /-shaped. 



AsvxAPTA Loew. 

 Palpi small, the last joint but little or not at all longer than the penul- 

 timate; anterior cross-vein but little curved. Winnektzia Rondani. 



11. The third longitudinal vein terminates before the tip of the wing; fifth 



vein not furcate. Spaniockua Winnertz. 



The third vein terminates at or beyond tlu' tip of the wing; fifth vein 

 furcate Aspuondvlia Loew. 



12. Proboscis much elongated, directed downward. Clisoimiyncha Loew. 

 Proboscis short. .......... l-J 



13. Metatarsi shorter than the following joint. . Lasioi'Ti:ra Meigen. 

 Metatarsi longer than the following joint. . ])iomyza Stephens. 



14. Wings with but two longitudinal veins, the first and fiftli, the latter not 



furcate, and neither reaching beyond the middle of the wing. 



Hktkkopkza Winnerlz. 

 Wings with three longitudinal veins, the first, tliird and fifth, the third 

 reaching to tlic tiji of llie wing, the fifth not furcate. 



MiASToK Mcinert 



