Key to genera and species of Psilopini from the Saudi Arabia

1. Arista at most with 3-4 dorsal rays; distance between reclinate and larger proclinate fronto-orbital setae greater than between reclinate seta and medial vertical seta; setae generally pale................... Scoliocephalus monochaeta Steyskal, 1968

- Arista with at least 5-6 dorsal rays; reclinate and proclinate fronto-orbital setae much closer together than reclinate seta and medial vertical setae; setae generally dark..................................................................2.

2 Vein R 2+3 close to costa beyond end of vein R 1; crossvein dm-cu with sharp angle at middle............................................................................................. Clanoneurum cimiciforme (Haliday, 1855)

- Vein R 2+3 well separated from costa; crossvein dm-cu mostly straight or shallowly arched, not angulate.................3.

3. Pedicel conical, broader apically, without dorsoapical lobe, dorsoapical seta weak (at most 1/3 as long as basal flagellomere); basal flagellomere from 2- 4X as long as high................................. Ceropsilopa longicornis (Lamb, 1912)

- Pedicel short and subtriangular, with dorsoapical lobe and bearing well-developed dorsoapical spine (at least half as long as basal flagellomere); basal flagellomere at most twice as long as high.............................................4.

4. One strong facial seta; pedicel with dorsoapical spine strong and nearly as long as basal flagellomere; presutural supra-alar seta moderately developed, length smaller than anterior notopleural seta..................... Psilopa nilotica (Becker, 1903)

- Two strong facial setae; pedicel with dorsoapical spine weak and at most 1/3 as long as basal flagellomere; presutural supra-alar seta well developed, length greater than anterior notopleural seta................................. Diasemocera Bezzi