84 THE BRITISH WOODLICE.
BRITISH LOCALITIES:—
England: Warley, Essex; (W.M.W.): Copthorne Common,
Surrey; (Stebbing, 70).
FOREIGN DISTRIBUTION:—
Europe: France; (25): Sweden, Denmark, Germany; (59): Turkey; (8).
Family—TRICHONISCIDAE.
Flagellum with less than ten joints; head with lateral
lobes; tail appendages partly hidden.
Genus—TRICHONISCUS Brandt, 1833 (3), p. 174.
Abdomen narrow; eyes compound; flagellum, usually with more than
three joints
In Trichoniscus the flagellum may have from seven to four
(rarely three) joints, As in Trichoniscus and Haplophthalmus there
are lateral lobes to the head, though these are not very
pronounced ; the body is also of small size, the abdomen narrow
with both divisions of the tail appendages equally so, and almost
of the same length though slightly covered by the last segment.
The compound eyes distinguish Trichoniscus from the two genera
named, and from Platyarthrus, while its small size and the
character of its tail-parts mark it out from all others.
Trichoniscus pusillus Brandt. Plate III.
1833 Trichoniscus pusillus Brandt (3), p. 174, pl. IV., fig. 9.
1838 Itea riparia Koch (34), part 22, pl. XVII.
1844 Itea laevis Zaddach (77), p. 16.
 1857 Philougria celer Kinahan (32), p. 281, pl. XXII., figs. 1—4.
1858 Philougria riparia Kinahan (33), pp. 191 and 198, pl. XXIII., fig. 1.
1868 Philougria riparia Bate and Westwood (1), p. 456.
2898 Trichoniscus pusillus Sars (59), p. 161, pl. LXXII, fig. 1.
This tiny species is found commonly amongst the roots of
the herbage in very moist places. It presents a horny translucent
appearance and is of a reddish brown colour. It runs with
considerable speed, and when it is moving, the white irregular
lines with which it is beset are not evident. Trichoniscus pusillus
is very much like Trichoniscus vividus in colour but the latter
species is nearly twice as big and has from five to seven joints
to the flagellum, while the former has never more than four.
Trichoniscus roseus is also much larger and its bright red colour
(which it loses, however, when preserved in alcohol) is
another means of distinguishing it from the species under
consideration.