Folsomia similis is a rare species. It is white spotted with black, has 1+1 ocelli (Fig. 1) and reaches a maximum length of 1.0 mm. The body setae are very short; the ratio of the length of the longest setae at the tip of the abdomen/length of mucro is about 2.0. The manubrium has 4+4 apical ventral (anterior) setae with 1+1 in a transverse row, 2+2 above these and 1+1 above these (Fig. 2; this is variable with 3+3 and 3+4 seen). The dens has 12-16 ventral (anterior) setae and 5 dorsal (posterior) setae. The post-antennal organ (PAO) is narrow and is longer than the width of ant1.
     There are three specimens in the NHML, all collected by Bagnall. The holotype from Bridlington is a female of 1.0 mm in length. The other specimens are a male of 0.9 mm from Kew Gardens, and an individual (sex not clear) from a garden in Chiswick.
     Folsomia similis is almost identical with Folsomia diplophthalma sensu Potapov & Dunger 2000. The only differences are that Folsomia diplophthalma has 4+4 latero-distal setae on the ventral tube and lateral teeth on the claws whereas Folsomia similis has only 3+3 latero-distal setae on the ventral tube (Fig. 3) and no lateral teeth on the claws. It is probably best to retain them as separate species for the present, but it is possible that Folsomia similis may eventually be sunk as a junior synonym under a broader definition of Folsomia diplophthalma.

Back to main page

Fig. 1 (above): Post-antennal organ (PAO) and single ocellus of Folsomia similis collected from Kew Gardens in February 1943 by Bagnall.

Fig. 3 (above): Folsomia similis collected from a garden in Chiswick, London in March 1943 by Bagnall. The ventral tube (VT) has 3 laterodistal setae (*). The 3 laterodistal setae on the other side of the ventral tube are out of the plane of focus.

Fig. 2 (above): Same specimen of Folsomia similis shown in Fig. 1. The manubrium has 4+4 ventral (anterior) setae (*); d, dens.