Genus Folsomia Willem, 1902.
Generally unpigmented species, with ocelli reduced in number or entirely absent. Abd. segments IV, V, and VI fused. Empodial appendage present, Furcula present, mucro with two or three teeth. Dens, basally, generally with two large teeth or hooks on inner edge. In his paper in 1937 Womersley reported three cosmopolitan species of this genus as being found in New Zealand at Pukekaroro Creek, Hillsborough, Auckland, but only one of these species has been found again, namely, F. fimetarioides which was amongst a collection of S. termitum sent to me by Mr. E. D. Pritchard and collected from Niger Bay, Onehunga, Auckland.
|1.||Species with two ocelli to each side.||F. quadrioculata Tullberg|
|Species with less than two ocelli.||2|
|2.||Mucro tridentate, ocelli absent.||F. fimetarioides Axelson|
|Mucro bidentate, one ocellus to each side.||F. diplopthalma Axelson|
Folsomia fimetarioides Axelson, 1903. Plate 49, figs. 152–153.
Colour: White or yellowish.
Clothing: Of moderately long stout setae.
Body: Length up to 1·5 mm. Antennae twice as long as head. Ant. I:II:III:IV as 10:20:15:27. Ant. IV with ten sensory hairs, apical knob, and sub-apical papilla. Ocelli absent. Post-antennal organ narrow, straight, and double-outlined.
Legs: Claw without any teeth, empodial appendage lanceolate and half as long as claw. Tenent hairs absent.
Furcula: Almost reaching ventral tube, dens twice as long as manubrium, strongly annulated. Mucro tridentate, apical tooth long and equal to pre-apical, basal tooth smaller. Sometimes a fourth very small tooth near centre. Dens corrugated.
Folsomia diplophthalma Axelson, 1902. Plate 49, figs. 159–160.
Dirty grey or white in colour and measuring up to 1·2 mm. in length Antennae equal to head in length. A single ocellus to each side. Post-antennal organ from 4–7 times as long as ocellus. Claw without any teeth and from 2–3 times length of empodial appendage. Tenent hairs absent. Furcula short, dens and manubrium approximately equal in length. Mucro bidentate, pre-apical tooth the larger. Dens corrugated.
Folsomia quadrioculata Tullberg, 1871. Plate 49, figs. 154–158.
Colour: Dirty pale grey to greyish-black.
Clothing: Densely clothed with long, stiff, simple setae.
Body: Up to 1 mm. in length. Two ocelli to each side, each on its own pigment spot. Post-antennal organ narrow, three to four times as long as an ocellus, parallel-sided, and slightly curved. Ant. IV with terminal knob, sub-apical papilla and numerous sensory hairs.
Legs: Claw without teeth, empodial appendage lanceolate and from one-third to one-half as long as claw. Tenent hairs absent.
Furcula: Not quite reaching Abd. II. Manubrium: dens: mucro as 5:3:1. Mucro bidentate, apical tooth smaller and slightly hooked. Dens strongly corrugated.