Xanthia ruticilla (Esper, 1791)
Spudaea ruticilla (Esper, 1791)
Agrochola ruticilla (Esper, 1791)

The placement of this species into a genus is discussed controversially. It has long been placed in the genus Spudaea, but recent authors either place it in Xanthia or in Agrochola. The placement into Xanthia is strongly supported by the larvae; indeed, the larvae of Xanthia ruticilla and of the type species of Xanthia, Xanthia togata, are virtually identical. In addition, the coloration of the adults of Xanthia ruticilla is very similar to some members of Xanthia, e.g. Xanthia gilvago. The placement into Agrochola as advovated by e.g. Haslberger and Segerer (2016) is more problematic. Agrochola is an assemblage of species that differ substantially in adult wing patterns, and have very different larval types (e.g. the slim and long, green larva of Agrochola humilis vs. the stout, dark larva of Agrochola macilenta). Thus, Agrochola is apparently a mingle-mangle of species and not a monophyletic group: not all current members of Agrochola appear to be conspecific with the type species Agrochola lychnidis. As an imago the present species is superficially similar to Agrochola lychnidis, but the larvae differ substantially in color and morphology. Therefore, I adopt the notion that the present species belongs to Xanthia; however, a revision of the phylogeny of Xanthia and its allied genera is urgently needed to clarify the interrelationships of these closely related species.