62 Ptych$ [April 



Third antennal joint ovate or oblong-ovate, not more than four times as long 

 as broad, the first joint shorter than the second; center of face gibbose 

 (Caliope and Xangelina) or not (Sapromyza and Minettia) 10 



3. Wings short and broad, brown; second vein arched forward; scutellum long and 



flat; four rows of acrostichals, the middle rows very indefinate; arista plumose. 



(N. J.; Fla., Aldrich; Ga.*) . . . . • Lauxania latipennis Coquillett. 



Wings not abnormally broad and short, the submarginal cell not broadened 

 at the expense of the marginal ; scutellum shorter 4 



4. Knob of halteres black; calypteres and fringe dark; base of wings darker than 



remainder; arista short-plumose; front legs black, the posterior tibiae and 



tarsi brown 5 



Halteres yellow or white; calypteres rarely dark; wings not blackened at base; 

 arista white 7 



5. Scutellum convex; body and head polished; periorbits broad, coeruleous, the 



median vitta of front shining black. Eur.*, N. Scot., Mass.*, N. Y.*, 

 (N. J., Pa., Mich., Wise. Aldrich), Ga., N. Mex., Queb.*, Ont.*, B. C,*, 



Alaska*. (Fig. 10.) Lauxania cylindricornis Fabricius. 



Scutellum flat, white pollinose; mesonotum white pollinose except a narrow 

 median stripe and the sides broadly; pleurae with two white pollinose spots . . 6 



6. Face completely white pollinose; front opaque with the sides white pollinose, 



a lateral vitta cinereous and the median vitta black; arista dark except base. 



Fla., N.J Lauxania opaca Loew. 



Face with a middle line and lateral vitta? more or less white-pollinose, otherwise 

 shining; front shining black except the narrow orbits, but viewed from above 

 showing a black median vitta and lateral black spots circumscribed with 

 white pollen; arista pale, (facialis Coquillett) Fla., Ga.*, La.*; Tenn. 

 Aldrich : Lauxania trivittata Loew. 



7. Arista densely pubescent with appressed white hairs; front shining black 8 



Arista loosely plumose; center of front opaque black; legs largely whitish 9 



8. Mesonotum and scutellum whitish pruinose; front tibiae and tarsi black; 



front femora and posterior legs brownish; lunule red; 3 dorsocentrals, 4 

 aerostichal rows. Ariz.; Mono Lake, Cal. Aldrich. 



Lauxania nigrimanus Coquillett. 



Head, thorax and abdomen shining, with slight coppery tinge; legs brownish 

 but the posterior femora largely black; 4 dorsocentrals, 2 aerostichal rows. 

 Cal.* Lauxania albiseta Coquillett. 



9. Scutellum velvety black except at base; legs whitish, the coxae and femora black; 



wings yellowish. N. J., Pa., Ga.; Kans., Tenn. Aldrich. 

 Lauxania f emoralis Loew. 



Scutellum shining, lightly white pollinose; front legs cf black from end of femora 

 to tip of metatarsi, remainder of front tarsi white; costal part of wings yel- 

 lowish, apex and posterior part infuscated. Pa. 



, Lauxania manuleata Loew. 



10. Face more or less protuberant in center, in part at least polished, although some- 

 times with oral, orbital or subantennal pruinose markings; halteres yellow. . 11 



Face flat or concave, wholly silvery, white, yellow or gray pruinose, or other- 

 wise marked with pollen, not polished; halteres sometimes black 24 



