Ex Microtus arvalis (Pallas) (common vole) (Cricetidae); collection locality: Tuv Province, Ulaanbaatar (Kéler, 1967 [Nr. 37, Nr. 88, Nr. 89/90]).
Ex Microtus sp. (undetermined vole) (Cricetidae) (Krištofıḱ, 1999); collection localities: Huvsgul Province, Ih-Horoo Gol; Selenge Province, Hyalganat (Krištofıḱ, 1999).
Ex Clethrionomys (now Myodes) sp. (undetermined vole) (Cricetidae), collection locality: Uvs Province, Harhiraa Uul (Krištofıḱ, 1999).
Ex Lasiopodomys brandtii (Radde) (Brandt’s vole) (Cricetidae); collection localities: Arhangai Province, Ugii Nuur; Tuv Province: Ulaanbaatar; Zavhan Province, Telmen Nuur (Kéler, 1967 [Nr. 185, Nr. 1243], Krištofıḱ, 1999).
New collections: Ex Microtus gregalis (Pallas) (narrow-headed vole) (Cricetidae); Bayan Olgii Province, Songinot Gol, 1 August 2015 (NK270442); Uvs Province, Harhiraa Mountain, Tsunheg, 8 August 2015 (NK270660), Juveriin Gol, 9 August 2015 (NK270687).
Ex Microtus oeconomus (Pallas) (tundra vole) (Cricetidae); Bayan Olgii Province, Songinot Gol, 31 July 2015 (NK270348); Huvsgul Province, Heegtsar River Valley, 19 August 2015 (NK272167, NK 272171); Uvs Province, Han Huhii Mountain, Baruun Turuun River Valley, 14 August 2015 (NK270946).
Ex Microtus sp. (undetermined vole) (Cricetidae); Bayan Olgii Province, Songinot Gol, 1 August 2015 (NK270431, NK270440).
Notes: Hoplopleura acanthopus parasitizes many species of voles across the Holarctic region (Durden and Musser, 1994). However, we report 2 new host associations for this louse in Mongolia —from M. gregalis and M. oeconomus. The collections of this louse from L. brandtii reported by Kéler (1967) were listed as ‘‘ Hoplopleura acanthopus ssp.’’ The following names are synonyms or former generic or subspecific assignments for this louse as documented by Durden and Musser (1994): Pediculus acanthopus Burmeister, 1839; Haematopinus acanthopus (Burmeister, 1839); Polyplax acanthopus (Burmeister, 1839); Hoplopleura acanthopus acanthopus (Burmeister, 1839); Polyplax villosa Galli-Valerio, 1905; Hoplopleura acanthopus var. americanus Kellogg and Ferris, 1915; Hoplopleura acanthopus var. aequidentis Fahrenholz, 1916; Hoplopleura acanthopus var. edentulus Fahrenholz, 1916 (partim); Hoplopleura fahrenholzi Eichler, 1952; Hoplopleura silesica Eichler, 1952.