Folsomia inoculata is a rare species that has only been recorded from four localities in Britain and Ireland. It is white with 0+0 ocelli and reaches a maximum length of 2.0 mm. The ratio of the length of the longest setae at the tip of the abdomen/length of mucro is between 2.5 and 2.8. The manubrium has 2+2 or 2+3 apical ventral (anterior) setae arranged longitudinally (Fig. 1). The dens has 8-12 ventral (anterior) setae and 4 dorsal (posterior) setae (3 at the base of the dens and one seta in the middle which is sometimes absent). The PAO is narrow and constricted and is slightly longer than the width of ant1 (Fig. 2). One characteristic feature is that the apical pair of posterior setae on the ventral tube are much longer than the others (Fig. 3). Another is the strange claw-like chitinous outgrowths near the base of the dens (Fig. 4).
The only Folsomia inoculata that Stev Hopkin saw were 'hiding' among specimens labelled as Folsomia 'spinosa' in the NHML slide collection. There are 34 individuals (on four slides) collected in January 1964 from Pullwyke Bay, Windermere. Subsequently Adam Garside turned up large numbers of this species in forest litter in the Dawyck cryptogamic sanctuary, Peebles (initially mis-identified as Folsomia candida) where this rare species appears to be the commonest springtail!