MORTH AMERICAN DIPTERA. 231 



7. — Scutellum yellow, or with base narrowly black , 8. 



Scutellum black, or with a uarrow apical margin of yellow 10. 



8. — Fourth segment with a small dorsal triangle, vertex of the 9 black. 



iiormula Lw. 

 Fourth and fifth segments with |small dorsal triangles, vertex of the 9 



yellow norma Wied. 



9. — Dorsal triangles on the third and fourth segments, that on the fourth (and 

 sometimes the third) connected with the lateral margins. 



uniliitibata Lw. 

 Dorsal triangle wanting on the third, that on the fourth obsolete or wanting, 



wings unusually dark seiiaria Lw. 



10. — Abdomen with narrow lateral markings. 11. 



Abdomen wholly black % ( 9 unknown) ueTadie Bigot. 



11.— Fifth segment with a dorsal line ; lateral markings on the segments of the 



9 very narrow Ifleigeilii Wied. 



Fifth segment with a dorsal triangle ; lateral markings on the segments of 



the % 9 prominent apiciila Lw. 



12. — Pile ou the thorax unusually long and dense ; abdomen wide, third and 



fourth segments very convex discalis Lw. 



Pile ou the thorax normal ; abdomen narrow, and third and fourth segments 



noticeably convex quateruaria Lw. 



13. — Face of 9 yellow, % black; abdomen with a wide, maculated or indentated 



lateral margin ; variable maculosa Loew. 



Face of % 9 yellow ; with a longitudinal line of black ; abdominal mark 

 ings transverse, the same in both sexes ; eyes of 9 glabrous. 



ba<lius Walker. 



Group mutahile. 



14. — Abdomeu : bands on the second segment interrupted, third and fourth con- 

 tinuous 15. 



Abdomen ; fourth and fifth segments only with wide yellow l)ands. 



mutabilis Fabr. 



15.— Scutellum % black 16. 



Scutellum % 9 yellow coustaiis Lw. 



16. — Abdomen ; bauds on the second and third continuous. 



Gerstaeckeri Bell 

 Abdomen ; second segment with two large spots bimaetilata Bell. 



Stratiomyia barbata Loew (PI. iii, tigs. 1 and 3). 



Strntioinyia hnrhata Loew, Centur. vi, 9. 



Stratiomys diademata Bigot, Ann. Soc. Ent. France, xxxviii, 23. 



Stratomi/s calopns Bigot, Ann. Soc. Ent. France, xxxviii, 23. 

 % 9 • Length 13 mm. % . — Face black, with blackish pile around the base 

 of antennae, and yellowish pile below ; a large spot on each side of the facial 

 prominence, and the lateral and lower part of tlie occiput yellow ; the occiput is 

 laterally very prominent, apparently ending abruptly towards the vertex, where 

 it becomes black and obscured by the eye, which extends to the edge of the ver- 

 tical angle. Antenusp. black. Thorax black, with blackish pile ; scutellum yel- 

 low, base aud sides black, spiues reddish ; halteres green. Abdomen black, with 

 yellowish pile and lateral markings, second segment with a large triangular spot 



TRANS. AM. ENT. SOC. XXII. JULY. 1895. 



