102 THE BRITISH WOODLICE.
Family—ARMADILLIDIIDAE.
Tail appendages not projecting when the animal
is walking.
Genus—ARMADILLIDIUM Brandt, 1833 (3), p. 184.
Flagellum, with two joints ; outer division of the tail appendages
expanded and broader at the hinder end.
The members of the genus Armadillidium are more likely to
be confounded, by the uninitiated, with the "Pill-millipedes"
than with other Woodlice. Excepting Cylisticus (which has
long pointed tail appendages) no other British forms have the
power of rolling themselves up into a complete ball. The
very arched body is characteristic of Armadillidium, and so is
the groove into which the basal joints of the antennae fit when
the creatures curl up.
The first two abdominal appendages only are provided with
air-tubes.
Armadillidium nasatum Budde-Lund,
1885. Plate XXII:
1885 Armadillidium nasatum Budde-Lund (8), p. 51.
1892 Armadillidium nasatum Dolltus (14), p. 10, fig 12.
1899 Armadillidium nasatum Norman (misprinted Porcellidium)
(49), p. 57. pl. VI., figs, 5-8.
Armadillidium nasatum has a narrow but very
prominent frontal lobe, which is almost square
and curves somewhat upwards and backwards.
The. joints of the flagellum are approximately
equal, and are together of the same length as
the last peduncular joint.
The telson is as long as it is broad at the
base, and tapers to a roundish point, while its
sides are slightly incurved.
The outer divisions of the tail appendages
are considerably longer than broad, and are
more or less paddle-shaped.
It will be noticed that the slope from thorax
to telson is more gentle than in the common species, Armadillidium
vulgare, and the first thoracic segment is not so greatly developed.
Consequently the species which we are considering does not
produce a perfect sphere, and the antennae are not hidden when