Key to tribes and genera of Hydrelliinae from the Saudi Arabia

1. Posterior notopleural seta inserted conspicuously above level of anterior seta.......................... Atissini Cresson

- Posterior notopleural seta at same level as anterior seta.......................................................2.

2. Eye bearing short, dense setulae; ocellar setae seldom as strong as pseudopostocellar setae, usually much weaker; postsutural supra-alar seta usually short, not longer than posterior notopleural seta........................................................................................ Hydrelliini Robineau-Desvoidy (genus Hydrellia Robineau-Desvoidy)

- Eye appearing bare; ocellar setae stronger than the weak pseudopostocellar setae; postsutural supra-alar setae strong, longer than posterior notopleural seta...........................................................................3.

3. Midtibia lacking dorsal, spinelike setae; shiny black to shiny dark green species, at most thinly microtomentose............................................................. Typopsilopini Cresson ( Typopsilopa jordaniensis Stuke, 2012)

- Midtibia with 1-4 erect, spinelike setae along dorsal surface; usually dull, microtomentose species..................... 4

4. Costa extended to vein M; dorsocentral setae 4 (1+3) or 1 (0+1)................................. Dryxini Zatwarnicki

- Costa extended to vein R4+5; dorsocentral setae 3 (1+2)..................... Notiphilini Fallén (genus Notiphila Fallén)