The genus Chaetosiphella Hille Ris Lambers, 1939 is discussed. Chaetosiphella stipae Hille Ris Lambers, 1947 is redescribed (apterous viviparous female) and its subspecies C. stipae setosa subsp. nov., (apterous viviparous female, oviparous female and apterous male) is described and figured in detail on the basis of specimens collected from Calamagrostis argentea, Calamagrostis arundinacea and Stipa sp. in France. A new species, Chaetosiphella longirostris sp. nov., is described and figured in detail on the basis of specimens collected from Ammophila arenaria in Portugal. A key to the identification of the species of the genus Chaetosiphella as well as differences from related species are given. Notes about distribution and host plants are shown.