*montigena Stach, 1946
Folsomia spinosa is moderately common and is probably widespread. It is white with scattered pigment, has 0+0 ocelli and reaches a maximum length of 1.1 mm. The body setae are numerous and long; the ratio of the length of the longest setae at the tip of the abdomen/length of mucro is between 4.0 and 4.5. The manubrium has 4+4 (rarely 4+3) apical ventral (anterior) setae with 3+3 in a transverse row and 1+1 above (Fig. 1). The dens has 12-14 ventral (anterior) setae and 4 dorsal (posterior) setae. The PAO is narrow and is about the same length as, or slightly longer than, the width of ant1 (Fig. 2). In well-cleared specimens of Folsomia penicula, the 2+2 ocelli may be difficult to resolve (especially the posterior pair) and care should be taken not to confuse this species with Folsomia spinosa.