Key to the species

1 Knob of haltere blackish-brown. Anepisternum without an interspatial seta (supplementary seta) in posterior row. [Mentum of proboscis wholly shining. Mid tibia with 1 ventral and 1 posteroventral seta. Notopleuron with setulae in addition to the setae. Hind tibia with 2 short posterodorsals.].................................................... S. khrulevae Sorokina

- Knob of haltere yellow. Anepisternum with an interspatial (supplementary seta) seta in posterior row................... 2

2 Mid tibia with 1–2 posteroventrals in addition to the ventral setae. Proboscis shorter, the prementum dusted behind. Arista with the longest combined pubescence one-third the width of postpedicel. Presutural acrostichals in multiple rows and with only a few of the outer ones slightly stronger than the acrostichal ground-setulae. ♂: abdominal tergites 3 and 4 with the black spots coalescing and therefore almost wholly black (Fig. 5). ♀: abdomen matt black with a little grey dust on tergite 4 anterolaterally, tergite 5 almost wholly grey (Fig. 7)......................................................... S. taeniata (Stein)

- Mid tibia with one seta on ventral surface, or slightly posterior of ventral, and without posteroventral setae. Proboscis long, thin, the prementum completely shining. Arista with the longest combined pubescence half or more of the width of postpedicel. Presutural acrostichals with the setae in the outer rows conspicuous and at least (1.5–) 2–3 times as long as any adjacent acrostichal ground-setulae. ♂: abdominal dust yellowish-brown, tergites 3 and 4 each with a pair of large, quadrate, distinct black spots (Figs 1, 4). ♀: abdomen yellowish-brown dusted, mostly without trace of dark spots (Fig. 6)................ 3

3 Notopleuron bare around the 2nd seta, occasionally with a few short setulae near base of 1st seta. Arista with the longest combined pubescence just over half the width of postpedicel...................................... S. dispar (Fallén)

- Notopleuron with a few very short setulae near base of 2nd seta. Arista with the longest combined pubescence half the width of postpedicel......................................................................... S. paradispar sp. nov.