b. Hypopleuræ without a vertical row of macrochætæ. MUSCINÆ c. Arista bare; distal portion of M_{1+2} broadly curved at the end; hypopleuræ with a sparse cluster of fine hairs. _S. braziliana_, Southern States and southward. _Synthesiomyia_ B. B. cc. Arista pectinate or plumose. d. Arista pectinate. _H. vittigera_, with the posterior half of the abdomen metallic blue. Mexico. _Hemichlora_ V. d. W. dd. Arista plumose. e. Middle tibia with one or more prominent setæ on the inner (flexor) surface beyond the middle, or inner surface very hairy. f. R_1 ends distad of the m-cu crossvein; M_{1+2} with a broad curve near its apical end. (= _Neomesembrina_ Schnabl. = _Metamesembrina_ Town). _M. meridiana._ Europe. _Mesembrina_ Meigen ff. R_1 ends proximad of the m-cu crossvein. g. Eyes pilose, sometimes sparsely in the female. h. Female with two or three stout orbital setæ; the hind metatarsus of the male thickened below at the base and penicillate. _D. pratorum._ Europe. _Dasyphora_ R. D.[M] hh. Neither sex with orbital setæ. i. Abdomen without macrochætæ; arista plumose. _C. asiatica._ Eastern Hemisphere. _Cryptolucilia_ B. B. ii. Abdomen with strong macrochætæ; arista very short-plumose, nearly bare. _B. tachinina._ Brazil. _Reinwardtia_ B. B. gg. Eyes bare. h. Body densely pilose; thoracic macrochætæ wanting; middle tibiæ much elongate and bent; last section of M_{1+2} with a gentle curve. H. (_Mesembrina_) _mystacea, et al._, Europe and _H. solitaria_, N. America. _Hypodermodes_ Town. hh. Body not densely pilose. i. Dorsocentrals six; last section of M_{1+2} with a gentle curve. j. Inner dorsocentrals ("acrostichals") wanting; sternopleurals arranged 1:3. _P. cyanicolor_, _cadaverina_, etc. Europe and America _Pyrellia_ R. D. jj. Inner dorsocentrals ("acrostichals") present; sternopleurals arranged 1:2. E. _latreillii._ North America. _Eumesembrina_ Town. ii. Dorsocentrals five; inner dorsocentrals present; last section of M_{1+2} with a rounded angle; sternopleurals arranged 1:2. _P. cornicina_ Europe and America. (_Pseudopyrellia_ Girsch.) _Orthellia_ R. D. ee. Middle tibia without a prominent bristle on the inner surface beyond the middle.