Key to genera and subgenera of Gymnomyzini from the Saudi Arabia

1. Anterior and posterior notopleural setae present ( Athyroglossa Loew)...........................................2.

- Anterior notopleural seta lacking.........................................................................3.

2. Mesonotal setulae in regular rows; fore femur without posteroventral, spinelike setulae; aristal rays relatively short, length of longest rays about 1/2 or less width of 1st flagellomere (subgenus Parathyroglossa Hendel).................................................................................................. Athyroglossa ordinata Becker, 1896

- Mesonotal setulae in irregular rows; forefemur bearing 3–7, short, posteroventral, spinelike setulae; aristal rays relatively long, length of longest rays equal or greater than half width of 1st flagellomere (Subgenus Athyroglossa Loew)....................................................................................... Athyroglossa argyrata Hendel, 1931

3. Face appearing spotted, pitted and pits with silvery gray microtomentum; anterior surface of midfemur rounded, bare of microtomentum, shiny; fore femur with posteroventral margin produced ventrally to a pointed ridge bearing setae............................................................................ Chlorichaeta orba Mathis & Zatwarnicki, 1993

- Face microsculptured but either bare or microtomentum in vertical stripes, unspotted; mid femur with anterior surface flat, densely microtomentose, microtomentum silvery white; fore femur bearing row of stout setae along apical half of posteroventral margin, these not arising from a pointed ridge................................... Mosillus beckeri (Cresson, 1925)