Momorangia binaloudensis Noei and Saboori sp. nov. (Acari: Trombidiformes: Erythraeidae) is described and illustrated from larvae, ectoparasitic on a moth, Apamea impedita (Christoph) (Lepidoptera: Noctuidae) from Iran. A key to larval species of the genus Momorangia is provided and the generic diagnosis is amended.