Sabella bavincourti Vaillant 1909 from the Eocene of northern France is a little-known trace fossil subsequently attributed – as Cteniza bavincourti – to the burrowing activities of a trapdoor spider. It is thus an ichnospecies name and not a body fossil. Its interpretation as the activity of a spider is questionable and its original assignment to a worm burrow seems intuitively more likely. Irrespective of the affinities of the producer, the ICZN also covers ichnotaxa such that classifying these structures under a modern genus name creates a homonym. It is here reassigned as the ichnotaxon Oichnus bavincourti comb. nov. Another problematic name is Theridium columbianum (Scudder 1878) from the Eocene of Canada and the USA, which is based on fossilized spider egg sacs. Under current ICZN rules fossil cocoons fall under the definition of “work of an animal”. We propose reassigning them here to Araneaovoidus igen. nov., as Araneaovoidus columbiae (Scudder 1878) comb. nov.; but stress that this is now a trace fossil name. Similar problems underlie fossilized galls attributed (probably correctly) to mites, but assigned to living eriophyid mite genera. Fossil galls are the preserved pathological reactions of plant tissue and are also not ichnotaxa sensu Bertling et al. (2006). We propose that these mite names lie outside the bounds of zoological nomenclature. Within the broader context of arachnid-related trace fossils we briefly review the literature on fossil spider webs, as well as putative arachnid trackways such as Paleohelcura Gilmore 1926 and Octopodichnus Gilmore 1927.