Hydrellia maura Meigen, 1838: 374: Hering 1950: 238 [host plant: Potamogeton perfoliatus L. (Potamogetonaceae)]; Deeming 2002: 55 [review].
Hydrellia modesta Loew 1860: 23: Brocher 1910: 170–176 [immature stages]; Séguy 1934: 430 [synonymy].
Hydropota modesta: Coe 1945: 396 [generic combination].
Hydrellia griseola variety modesta: Cresson 1932: 6 [revised status].
Hydrellia incana form modesta: Nye 1958: 441–443 [larva; host plants].
Specimens examined. 1 ♂, Asir, Abha, Hay Al-Nusub (Abha Farm Centre), 1–25. v. 2013, Malaise trap. H.A. Dawah (CERS); 1 ♂, same data but 23. viii.–13. x. 2013.
Distribution. This is the first record from Saudi Arabia and Arabian Peninsula. This species was described from Germany (Baiern) and further recorded from the Afrotropical Region: South Africa; Palaearctic Region: Algeria, Armenia, Austria, Azores, Belgium, Bulgaria, Canary Islands, Czechia, Egypt, Faroe Islands, Finland, Germany, Great Britain, Hungary, Italy, Jordan, Madeira Islands, Morocco, Netherlands, Poland, Romania, Spain, Madeira Islands, Sweden, Switzerland.