Shatalkin & Merz: (Genus Psilosoma): Two vertical setae. Postocellar seta absent. Notopleural seta absent. Dorsocentral seta present or absent. 1 (pair of) apical scutellar seta. Anepimeron bare. Hind femur in male (and also in the female of P. audouini) thickened. Male terminalia with long aedeagus. Female ovipositor compressed laterally and strongly sclerotized.
Espèces semblables : Psilosoma audouini possède 2 fins traits noirs sur le thorax. Le genre Psila possède une soie notopleurale
Jessica Joachim has an identification blog at Les carnets nature de Jessica
Collin, 1944: Psila (Camptopsila) lefebvrei : In this species the male hind femora, while dilated, are not tuberculate at base beneath as in Psilosoma audouini, and the prothoracic episterna in both sexes are not so microscopically pilose, but usually bear a few longer pale hairs. The female ovipositor is more normal, and the sixth tergite is without the tubercle on each side at base of P. audouini.
Shatalkin & Merz reported both Psilosoma spp. as being often swept and observed on large stands of green alder (Alnus viridis) see European Tree Atlas