DIPTEKA— BGIOMYZID^. 543 



Icngtli; tlio fiftli longitudinal vein is lost jnst before reaching the margin 

 and the sixth runs half-way to it; the second and thiid longitudinal veins 

 separate just over the extremities of the small basal cells, and originate 

 from a transverse vein which unites the first and fourth longitudinal veins 

 before the middle of the basal cells. 



Length of the wing, 4.5""° ; breadth, 2""". 



Quesnel, British Columbia. Three specimens, Nos. 2, 42, 43 (Dr. Gr. 

 M. Dawson, Geological Survey of Canada). 



SciOMYZA? MANCA. 

 PI. 4, Pig. 9; PI. 9, Figs. 1-6, 15, Iti, 18, 20, 23, 24, 28, 29. 



.SVii)mi/-((? maiica Scudd., Bull. IJ. S. Geol. Geogr. Surv. Torr., IV, 7.56-758 (1878). 



This fly, extremely abundant in the Green River shales — in fact out- 

 numbering all the other Diptera together — is temporarily placed in this 

 genus, because its characters seem to agree better with those of the family 

 Sciomyzidae than of any other ; yet it can not properly be placed in any of 

 the genera known to me. I should be inclined to place it near Blepharop- 

 tera in the Helomyzidfe, but all the tibiaj are bristled throughout. Its gen- ' 

 eral appearance is that of the Ephydrinidie, but the Inistl}- surface of the 

 middle tibise would allow us to place it only in the Notiphilina, from which 

 it is excluded by the want of pectinations on the upper side of the antennal 

 bristle. The want of complete neuration prevents me from designating it 

 at present by a new generic name, which it can hardly fail to require as 

 soon as that is known ; only two or three of the three-score specimens 

 before me have any important part of the wings, and this constant frag- 

 mentary condition of the fossils has suggested the specific name. The 

 genus in which it would fall may be partially characterized as follows : 

 Body compact, stout ; the head comparatively small, perhaps one-third the 

 bulk of the thorax, about three-fourths its width, with large, naked eyes, 

 the front between them nearly equal and pretty broad, obliquely sloped, 

 and slightly tumid on a side view, so as to project considerably below ; a 

 few curved bristles project from its summit. Antenna- with the Hagellum 

 subglobose, scarcely longer than broad, much larger than the joints of the 

 scape, and above bearing at its tip a curved, rather short, naked, tapering 

 style, scarcely longer than the flagellum proper and bluntly pointed ; iii 

 several specimens in which this part is pretty well preserved this is inva- 



